diff --git a/build/pkgs/sagelib/spkg-install.in b/build/pkgs/sagelib/spkg-install.in
index 2a638df17f1..e223e0d236c 100644
--- a/build/pkgs/sagelib/spkg-install.in
+++ b/build/pkgs/sagelib/spkg-install.in
@@ -55,7 +55,8 @@ if [ "$SAGE_EDITABLE" = yes ]; then
         --config-settings=build-dir="build/sage-distro" \
         --config-settings=setup-args="--native-file=$SAGE_PKGS/../platform/meson/sage-configure-native-file.ini" \
         --config-settings=setup-args="-DSAGE_LOCAL=$SAGE_LOCAL" \
-        --config-settings=setup-args="-Dbuild-docs=$SAGE_BUILD_DOCS"
+        --config-settings=setup-args="-Dbuild-docs=$SAGE_BUILD_DOCS" \
+        --config-settings=setup-args="-Ddefer_feature_checks=true"
 
     if [ "$SAGE_WHEELS" = yes ]; then
         # Additionally build a wheel (for use in other venvs)
@@ -73,7 +74,8 @@ else
     # Compiling sage/interfaces/sagespawn.pyx because it depends on /private/var/folders/38/wnh4gf1552g_crsjnv2vmmww0000gp/T/pip-build-env-609n5985/overlay/lib/python3.10/site-packages/Cython/Includes/posix/unistd.pxd
     sdh_pip_install --no-build-isolation . --config-setting=build-dir="build/sage-distro" \
         --config-setting=setup-args="-DSAGE_LOCAL=$SAGE_LOCAL" \
-        --config-setting=setup-args="-Dbuild-docs=$SAGE_BUILD_DOCS"
+        --config-setting=setup-args="-Dbuild-docs=$SAGE_BUILD_DOCS" \
+        --config-settings=setup-args="-Ddefer_feature_checks=true"
 fi
 
 # Remove (potentially invalid) star import caches.
diff --git a/conftest.py b/conftest.py
index 1ccd5f48d68..74f0747b50b 100644
--- a/conftest.py
+++ b/conftest.py
@@ -117,14 +117,37 @@ def _find(
                     pytest.skip("unable to import module %r" % self.path)
                 else:
                     if isinstance(exception, ModuleNotFoundError):
-                        # Ignore some missing features/modules for now
-                        # TODO: Remove this once all optional things are using Features
-                        if exception.name in (
-                            "valgrind",
-                            "rpy2",
-                            "sage.libs.coxeter3.coxeter",
-                            "sagemath_giac",
-                        ):
+                        # Ignore some missing features/modules for
+                        # now. Many of these are using custom
+                        # "sage.doctest" headers that only our doctest
+                        # runner (i.e. not pytest) can understand.
+                        #
+                        # TODO: we should remove this once all
+                        # optional things are using Features. It
+                        # wouldn't be too hard to move the
+                        # "sage.doctest" header into pytest (as
+                        # explicit ignore lists based on feature
+                        # tests), but that would require duplication
+                        # for as long as `sage -t` is still used.
+                        from sage.features.coxeter3 import Coxeter3
+                        from sage.features.sagemath import (sage__libs__eclib,
+                                                            sage__libs__giac)
+                        from sage.features.standard import PythonModule
+
+                        exc_list = ["valgrind"]
+                        if not sage__libs__eclib().is_present():
+                            exc_list.append("sage.libs.eclib")
+                        if not PythonModule("rpy2").is_present():
+                            exc_list.append("rpy2")
+                        if not Coxeter3().is_present():
+                            exc_list.append("sage.libs.coxeter3.coxeter")
+                        if not sage__libs__giac().is_present():
+                            exc_list.append("sagemath_giac")
+
+                        # Ignore import errors, but only when the associated
+                        # feature is actually disabled. Use startswith() so
+                        # that sage.libs.foo matches all of sage.libs.foo.*
+                        if any(exception.name.startswith(e) for e in exc_list):
                             pytest.skip(
                                 f"unable to import module {self.path} due to missing feature {exception.name}"
                             )
diff --git a/meson.options b/meson.options
index 294e1171b03..5c31cf4c95d 100644
--- a/meson.options
+++ b/meson.options
@@ -17,6 +17,16 @@ option(
   description: 'Build the HTML / PDF documentation'
 )
 
+# Useful on binary distros, for example, to allow features to flip on as soon
+# as the package that provides it is installed. If this is disabled, a rebuild
+# of sagelib is required to toggle features on or off.
+option(
+  'defer_feature_checks',
+  type: 'boolean',
+  value: false,
+  description: 'Defer feature checks to runtime'
+)
+
 #
 # Features
 #
diff --git a/src/doc/en/reference/spkg/index.rst b/src/doc/en/reference/spkg/index.rst
index e9ba934a540..bffd8afb9b7 100644
--- a/src/doc/en/reference/spkg/index.rst
+++ b/src/doc/en/reference/spkg/index.rst
@@ -31,6 +31,7 @@ Features
    sage/features
    sage/features/join_feature
    sage/features/all
+   sage/features/build_feature
    sage/features/sagemath
    sage/features/pkg_systems
    sage/features/bliss
@@ -52,10 +53,12 @@ Features
    sage/features/mcqd
    sage/features/meataxe
    sage/features/mip_backends
+   sage/features/mwrank
    sage/features/normaliz
    sage/features/pandoc
    sage/features/pdf2svg
    sage/features/polymake
+   sage/features/rankwidth
    sage/features/rubiks
    sage/features/tdlib
    sage/features/topcom
diff --git a/src/sage/config.py.in b/src/sage/config.py.in
index 3a95538d313..aca1247cc11 100644
--- a/src/sage/config.py.in
+++ b/src/sage/config.py.in
@@ -60,6 +60,17 @@ THREEJS_DIR = SAGE_LOCAL + "/share/threejs-sage"
 OPENMP_CFLAGS = "@OPENMP_CFLAGS@"
 OPENMP_CXXFLAGS = "@OPENMP_CXXFLAGS@"
 
+# build-time feature flags
+defer_feature_checks = @DEFER_FEATURE_CHECKS@
+bliss_enabled = @BLISS_ENABLED@
+brial_enabled = @BRIAL_ENABLED@
+coxeter3_enabled = @COXETER3_ENABLED@
+eclib_enabled = @ECLIB_ENABLED@
+mcqd_enabled = @MCQD_ENABLED@
+meataxe_enabled = @MEATAXE_ENABLED@
+rankwidth_enabled = @RANKWIDTH_ENABLED@
+sirocco_enabled = @SIROCCO_ENABLED@
+tdlib_enabled = @TDLIB_ENABLED@
 
 def is_editable_install() -> bool:
     """
diff --git a/src/sage/doctest/external.py b/src/sage/doctest/external.py
index 026ca7f08cd..e8afae17bbd 100644
--- a/src/sage/doctest/external.py
+++ b/src/sage/doctest/external.py
@@ -513,9 +513,20 @@ def detectable(self):
         """
         Return the list of names of those features for which testing their presence is allowed.
         """
+        # Exclude build features that aren't runtime detectable from
+        # the list. Note that when defer_feature_checks is not set,
+        # *no* BuildFeatures are runtime-detectable.
+        from sage.features.build_feature import BuildFeature
+        def build_time_only(f):
+            return ( isinstance(f, BuildFeature)
+                     and
+                     not f.is_runtime_detectable() )
+
         return [feature.name
                 for feature, seen in zip(self._features, self._seen)
-                if seen >= 0 and (self._allow_external or feature not in self._external_features)]
+                if seen >= 0
+                and (self._allow_external or feature not in self._external_features)
+                and not build_time_only(feature)]
 
     def seen(self):
         """
@@ -527,9 +538,18 @@ def seen(self):
             sage: available_software.seen() # random
             ['internet', 'latex', 'magma']
         """
+        # Exclude build features that aren't runtime detectable from
+        # the list. Note that when defer_feature_checks is not set,
+        # *no* BuildFeatures are runtime-detectable.
+        from sage.features.build_feature import BuildFeature
+        def build_time_only(f):
+            return ( isinstance(f, BuildFeature)
+                     and
+                     not f.is_runtime_detectable() )
         return [feature.name
                 for feature, seen in zip(self._features, self._seen)
-                if seen > 0]
+                if seen > 0
+                and not build_time_only(feature)]
 
     def hidden(self):
         """
diff --git a/src/sage/features/bliss.py b/src/sage/features/bliss.py
index f14893b5a89..450010f83a0 100644
--- a/src/sage/features/bliss.py
+++ b/src/sage/features/bliss.py
@@ -13,9 +13,11 @@
 #                  https://www.gnu.org/licenses/
 # *****************************************************************************
 
-from . import CythonFeature, PythonModule
-from .join_feature import JoinFeature
+from . import CythonFeature
 
+from sage.config import bliss_enabled
+from sage.features import PythonModule
+from sage.features.build_feature import BuildFeature
 
 TEST_CODE = """
 # distutils: language=c++
@@ -57,16 +59,19 @@ def __init__(self):
                                url='http://www.tcs.hut.fi/Software/bliss/')
 
 
-class Bliss(JoinFeature):
+class Bliss(BuildFeature):
     r"""
-    A :class:`~sage.features.Feature` which describes whether the :mod:`sage.graphs.bliss`
-    module is available in this installation of Sage.
+    A :class:`~sage.features.Feature` which describes whether the
+    :mod:`sage.graphs.bliss` module is available in this installation
+    of Sage.
 
     EXAMPLES::
 
         sage: from sage.features.bliss import Bliss
-        sage: Bliss().require()  # optional - bliss
+        sage: Bliss().require()  # needs bliss
     """
+    _enabled_in_build = bliss_enabled
+
     def __init__(self):
         r"""
         TESTS::
@@ -74,11 +79,27 @@ def __init__(self):
             sage: from sage.features.bliss import Bliss
             sage: Bliss()
             Feature('bliss')
+
         """
-        JoinFeature.__init__(self, "bliss",
-                             [PythonModule("sage.graphs.bliss", spkg='bliss',
-                                           url='http://www.tcs.hut.fi/Software/bliss/')])
+        super().__init__("bliss",
+                         url='http://www.tcs.hut.fi/Software/bliss/')
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
+
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.bliss import Bliss
+            sage: result = Bliss().is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs bliss
+            FeatureTestResult('bliss', True)
 
+        """
+        result = PythonModule("sage.graphs.bliss")._is_present()
+        result.feature = self
+        return result
 
 def all_features():
     return [Bliss()]
diff --git a/src/sage/features/build_feature.py b/src/sage/features/build_feature.py
new file mode 100644
index 00000000000..9c9bb0cd463
--- /dev/null
+++ b/src/sage/features/build_feature.py
@@ -0,0 +1,138 @@
+r"""
+Features that can be explicitly enabled or disabled at build time
+
+These features are unique in that, if they are enabled or disabled at
+build-time, then we usually do not want to detect them on-the-fly.
+Instead we trust the value supplied (or detected) at build-time. There
+is however an overrride to defer these checks to run-time (the classic
+behavior) for use on binary distros or anywhere it is desirable to
+enable/disable features without rebuilding sage.
+
+This is an implementation of Option 3 in `Github discussion 41067
+<https://github.com/sagemath/sage/discussions/41067>`__.
+"""
+
+from sage.features import Feature, FeatureTestResult
+
+class BuildFeature(Feature):
+    r"""
+    A class for features that can be enabled or disabled at
+    build-time.
+
+    The current implementation refers to build features that are
+    configurable in meson. For example::
+
+        option(
+          'foo',
+          type: 'feature',
+          value: 'auto',
+          description: 'support for foo'
+        )
+
+    At build time, support for this "foo" will be automatically
+    detected, and either enabled or disabled depending on whether or
+    not its requirements are met. Alternatively, users may pass either
+    ``-Dfoo=enabled`` or ``-Dfoo=disabled`` to explicitly enable or
+    disable the feature. Features may be disabled regardless of
+    whether or not they are installed, but usually features may only
+    be enabled if their dependencies are present and usable.
+
+    In any event, after ``meson setup``, support for "foo" is either
+    enabled or disabled, and a boolean variable called something like
+    ``foo_enabled`` is written to ``sage.config``. In your subclass,
+    you should set the member variable ``_enabled_in_build`` to the
+    value of that config variable.
+
+    The :meth:`_is_present` method for this class will return the
+    value of that config variable unless ``defer_feature_checks`` is
+    set to ``True`` in ``sage.config``. If checks are deferred, the
+    :meth:`_is_present` method will try to return the value of
+    :meth:`is_present_at_runtime` instead. If your feature can be
+    detected at run-time, you should implement that check in
+    :meth:`is_present_at_runtime`. Otherwise, leave it unimplemented;
+    and :meth:`_is_present` will return ``False``.
+
+    EXAMPLES::
+
+        sage: from sage.features.build_feature import BuildFeature
+        sage: BuildFeature("foo")
+        Feature('foo')
+
+    """
+
+    # Set this in subclasses.
+    _enabled_in_build = None
+
+    # Implement this method if your feature is detectable at run-time.
+    # Your test should only return True if the feature meets Sage's
+    # requirements; for example, if there are doctests for gzipped foo
+    # data files hidden behind "needs foo", then you should ensure
+    # that foo was compiled with (say) --enable-zlib in your check.
+    #
+    # def is_present_at_runtime(self):
+    #     pass
+
+    def is_runtime_detectable(self):
+        r"""
+        Return whether or not this feature can (and should) be
+        detected at runtime.
+
+        A feature is runtime detectable if both of the following hold:
+
+        - Deferred feature checks have been enabled globally by
+          passing ``-Ddefer_feature_checks=true`` to ``meson setup``.
+
+        - An ``is_present_at_runtime`` method has been implemented for
+          the feature.
+
+        EXAMPLES:
+
+        The method returns ``False`` if you have not implemented
+        ``is_present_at_runtime``::
+
+            sage: from sage.features.build_feature import BuildFeature
+            sage: bf = BuildFeature("example")
+            sage: bf.is_runtime_detectable()
+            False
+
+        """
+        from sage.config import defer_feature_checks
+        if not defer_feature_checks:
+            return False
+        elif hasattr(self, "is_present_at_runtime"):
+            return True
+        else:
+            return False
+
+    def _is_present(self):
+        r"""
+        Default presence check for build features.
+
+        If this feature :meth:`is_runtime_detectable`, we return the
+        result of that method. Otherwise, we use the value of
+        ``self._enabled_in_build``.
+
+        EXAMPLES:
+
+        When feature checks are deferred, runtime-detectable features
+        can be detected without ``self._enabled_in_build`` being set,
+        but this will fail by surprise when they are un-deferred::
+
+            sage: from sage.config import defer_feature_checks
+            sage: from sage.features.build_feature import BuildFeature
+            sage: bf = BuildFeature("example")
+            sage: const_True = lambda s: True
+            sage: bf.is_present_at_runtime = const_True.__get__(bf)
+            sage: (not defer_feature_checks) or bf.is_present().is_present
+            True
+
+        """
+        if self.is_runtime_detectable():
+            return self.is_present_at_runtime()
+        else:
+            import sage.config
+            # Wrap with bool() so that we can be lazy and use meson's
+            # set10() rather than painstakingly writing "True" and
+            # "False" to the config file.
+            result =  bool(self._enabled_in_build)
+            return FeatureTestResult(self, result)
diff --git a/src/sage/features/coxeter3.py b/src/sage/features/coxeter3.py
index 3fdc3c88e03..eed4d844e10 100644
--- a/src/sage/features/coxeter3.py
+++ b/src/sage/features/coxeter3.py
@@ -13,20 +13,24 @@
 #                  https://www.gnu.org/licenses/
 # *****************************************************************************
 
-from . import PythonModule
-from .join_feature import JoinFeature
+from sage.config import coxeter3_enabled
+from sage.features import PythonModule
+from sage.features.build_feature import BuildFeature
 
-
-class Coxeter3(JoinFeature):
+class Coxeter3(BuildFeature):
     r"""
-    A :class:`~sage.features.Feature` which describes whether the :mod:`sage.libs.coxeter3`
-    module is available in this installation of Sage.
+    A :class:`~sage.features.Feature` which describes whether the
+    :mod:`sage.libs.coxeter3` module is available in this installation
+    of Sage.
 
     EXAMPLES::
 
         sage: from sage.features.coxeter3 import Coxeter3
-        sage: Coxeter3().require()  # optional - coxeter3
+        sage: Coxeter3().require()  # needs coxeter3
+
     """
+    _enabled_in_build = coxeter3_enabled
+
     def __init__(self):
         r"""
         TESTS::
@@ -34,11 +38,31 @@ def __init__(self):
             sage: from sage.features.coxeter3 import Coxeter3
             sage: Coxeter3()
             Feature('coxeter3')
+
         """
-        JoinFeature.__init__(self, "coxeter3",
-                             [PythonModule("sage.libs.coxeter3.coxeter",
-                                           spkg='coxeter3')])
+        super().__init__("coxeter3", spkg='coxeter3')
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
 
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.coxeter3 import Coxeter3
+            sage: result = Coxeter3().is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs coxeter3
+            FeatureTestResult('coxeter3', True)
+
+        """
+        # The build system installs the sage/libs/coxeter3 source code
+        # even when coxeter3 support is disabled, so a naive import of
+        # that module will actually succeed. We check for a
+        # conditionally-compiled cython module instead.
+        cython_modname = "sage.libs.coxeter3.coxeter"
+        result = PythonModule(cython_modname)._is_present()
+        result.feature = self
+        return result
 
 def all_features():
     return [Coxeter3()]
diff --git a/src/sage/features/mcqd.py b/src/sage/features/mcqd.py
index 7f0df8eedda..95211ca4e69 100644
--- a/src/sage/features/mcqd.py
+++ b/src/sage/features/mcqd.py
@@ -11,21 +11,24 @@
 #                  https://www.gnu.org/licenses/
 # *****************************************************************************
 
-from . import PythonModule
-from .join_feature import JoinFeature
+from sage.config import mcqd_enabled
+from sage.features import PythonModule
+from sage.features.build_feature import BuildFeature
 
-
-class Mcqd(JoinFeature):
+class Mcqd(BuildFeature):
     r"""
-    A :class:`~sage.features.Feature` describing the presence of the :mod:`~sage.graphs.mcqd` module,
-    which is the SageMath interface to the :ref:`mcqd <spkg_mcqd>` library
+    A :class:`~sage.features.Feature` describing the presence of
+    the :mod:`~sage.graphs.mcqd` module, which is the SageMath
+    interface to the :ref:`mcqd <spkg_mcqd>` library
 
     EXAMPLES::
 
         sage: from sage.features.mcqd import Mcqd
-        sage: Mcqd().is_present()  # optional - mcqd
+        sage: Mcqd().is_present()  # needs mcqd
         FeatureTestResult('mcqd', True)
+
     """
+    _enabled_in_build = mcqd_enabled
 
     def __init__(self):
         """
@@ -34,11 +37,26 @@ def __init__(self):
             sage: from sage.features.mcqd import Mcqd
             sage: isinstance(Mcqd(), Mcqd)
             True
+
         """
-        JoinFeature.__init__(self, 'mcqd',
-                             [PythonModule('sage.graphs.mcqd',
-                                           spkg='mcqd')])
+        super().__init__('mcqd', spkg='mcqd')
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
 
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.mcqd import Mcqd
+            sage: result = Mcqd().is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs mcqd
+            FeatureTestResult('mcqd', True)
+
+        """
+        result = PythonModule("sage.graphs.mcqd")._is_present()
+        result.feature = self
+        return result
 
 def all_features():
     return [Mcqd()]
diff --git a/src/sage/features/meataxe.py b/src/sage/features/meataxe.py
index 3276b3cdba7..a8126661f0f 100644
--- a/src/sage/features/meataxe.py
+++ b/src/sage/features/meataxe.py
@@ -12,22 +12,25 @@
 #                  https://www.gnu.org/licenses/
 # *****************************************************************************
 
+from sage.config import meataxe_enabled
+from sage.features import PythonModule
+from sage.features.build_feature import BuildFeature
 
-from . import PythonModule
-from .join_feature import JoinFeature
-
-
-class Meataxe(JoinFeature):
+class Meataxe(BuildFeature):
     r"""
-    A :class:`~sage.features.Feature` describing the presence of the Sage modules
-    that depend on the :ref:`meataxe <spkg_meataxe>` library.
+    A :class:`~sage.features.Feature` describing the presence of
+    the Sage modules that depend on the :ref:`meataxe <spkg_meataxe>`
+    library.
 
     EXAMPLES::
 
         sage: from sage.features.meataxe import Meataxe
-        sage: Meataxe().is_present()  # optional - meataxe
+        sage: Meataxe().is_present()  # needs meataxe
         FeatureTestResult('meataxe', True)
+
     """
+    _enabled_in_build = meataxe_enabled
+
     def __init__(self):
         r"""
         TESTS::
@@ -35,11 +38,27 @@ def __init__(self):
             sage: from sage.features.meataxe import Meataxe
             sage: isinstance(Meataxe(), Meataxe)
             True
+
         """
-        JoinFeature.__init__(self, 'meataxe',
-                             [PythonModule('sage.matrix.matrix_gfpn_dense',
-                                           spkg='meataxe')])
+        super().__init__('meataxe', spkg='meataxe')
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
+
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.meataxe import Meataxe
+            sage: result = Meataxe().is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs meataxe
+            FeatureTestResult('meataxe', True)
 
+        """
+        modname = "sage.matrix.matrix_gfpn_dense"
+        result = PythonModule(modname)._is_present()
+        result.feature = self
+        return result
 
 def all_features():
     return [Meataxe()]
diff --git a/src/sage/features/mwrank.py b/src/sage/features/mwrank.py
new file mode 100644
index 00000000000..05182073961
--- /dev/null
+++ b/src/sage/features/mwrank.py
@@ -0,0 +1,54 @@
+r"""
+Feature for testing the presence of the ``mwrank`` program
+
+This is part of the eclib package.
+"""
+
+from sage.config import eclib_enabled
+from sage.features import Executable
+from sage.features.build_feature import BuildFeature
+
+
+class Mwrank(BuildFeature, Executable):
+    r"""
+    A :class:`~sage.features.Feature` describing the presence of
+    the ``mwrank`` program.
+
+    EXAMPLES::
+
+        sage: from sage.features.mwrank import Mwrank
+        sage: Mwrank().is_present()  # needs mwrank
+        FeatureTestResult('mwrank', True)
+
+    """
+    _enabled_in_build = eclib_enabled
+
+    def __init__(self):
+        r"""
+        TESTS::
+
+            sage: from sage.features.mwrank import Mwrank
+            sage: isinstance(Mwrank(), Mwrank)
+            True
+
+        """
+        Executable.__init__(self, 'mwrank', executable='mwrank',
+                            spkg='eclib', type='standard')
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
+
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.mwrank import Mwrank
+            sage: result = Mwrank().is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs mwrank
+            FeatureTestResult('mwrank', True)
+
+        """
+        return Executable._is_present(self)
+
+def all_features():
+    return [Mwrank()]
diff --git a/src/sage/features/rankwidth.py b/src/sage/features/rankwidth.py
new file mode 100644
index 00000000000..bfea87d457d
--- /dev/null
+++ b/src/sage/features/rankwidth.py
@@ -0,0 +1,49 @@
+r"""
+Feature for testing the availability of the ``rw`` library
+"""
+
+from sage.config import rankwidth_enabled
+from sage.features import PythonModule
+from sage.features.build_feature import BuildFeature
+
+class RankWidth(BuildFeature):
+    r"""
+    A :class:`~sage.features.Feature` for the availability of
+    the ``rankwidth`` library as determined at build-time.
+
+    This library is required for the rank-width graph decomposition
+    found in :mod:`sage.graphs.graph_decompositions.rankwidth`.
+
+    EXAMPLES::
+
+        sage: from sage.features.rankwidth import RankWidth
+        sage: RankWidth().is_present()  # needs rankwidth
+        FeatureTestResult('rankwidth', True)
+
+    """
+    _enabled_in_build = rankwidth_enabled
+
+    def __init__(self):
+        super().__init__("rankwidth", spkg="rw", type="standard")
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
+
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.rankwidth import RankWidth
+            sage: result = RankWidth().is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs rankwidth
+            FeatureTestResult('rankwidth', True)
+
+        """
+        modname = "sage.graphs.graph_decompositions.rankwidth"
+        result = PythonModule(modname)._is_present()
+        result.feature = self
+        return result
+
+
+def all_features():
+    return [RankWidth()]
diff --git a/src/sage/features/sagemath.py b/src/sage/features/sagemath.py
index 6313f1c715a..987e489474b 100644
--- a/src/sage/features/sagemath.py
+++ b/src/sage/features/sagemath.py
@@ -39,9 +39,10 @@
 #                  https://www.gnu.org/licenses/
 # *****************************************************************************
 
-from . import PythonModule, StaticFile
-from .join_feature import JoinFeature
-
+from sage.config import brial_enabled, eclib_enabled
+from sage.features import PythonModule, StaticFile
+from sage.features.build_feature import BuildFeature
+from sage.features.join_feature import JoinFeature
 
 class sagemath_doc_html(StaticFile):
     r"""
@@ -512,6 +513,63 @@ def __init__(self):
                              spkg='sagemath_ntl', type='standard')
 
 
+class sage__libs__eclib(BuildFeature):
+    r"""
+    A :class:`sage.features.Feature` describing the presence of
+    :mod:`sage.libs.eclib`.
+
+    EXAMPLES:
+
+    This module is runtime detectable if feature checks are deferred::
+
+        sage: from sage.features.sagemath import sage__libs__eclib
+        sage: from sage.config import defer_feature_checks
+        sage: e = sage__libs__eclib()
+        sage: (not defer_feature_checks) or e.is_runtime_detectable()
+        True
+
+    TESTS::
+
+        sage: from sage.features.sagemath import sage__libs__eclib
+        sage: sage__libs__eclib().is_present()  # needs sage.libs.eclib
+        FeatureTestResult('sage.libs.eclib', True)
+
+    """
+    _enabled_in_build = eclib_enabled
+
+    def __init__(self):
+        r"""
+        TESTS::
+
+            sage: from sage.features.sagemath import sage__libs__eclib
+            sage: isinstance(sage__libs__eclib(), sage__libs__eclib)
+            True
+
+        """
+        super().__init__("sage.libs.eclib", spkg="eclib", type="standard")
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
+
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.sagemath import sage__libs__eclib
+            sage: result = sage__libs__eclib().is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs sage.libs.eclib
+            FeatureTestResult('sage.libs.eclib', True)
+
+        """
+        # The build system installs the sage/libs/eclib source code
+        # even when eclib support was disabled, so a naive import of
+        # that module will actually succeed. We check for a
+        # conditionally-compiled cython module instead.
+        result = PythonModule("sage.libs.eclib.mwrank")._is_present()
+        result.feature = self
+        return result
+
+
 class sage__libs__giac(JoinFeature):
     r"""
     A :class:`sage.features.Feature` describing the presence of :mod:`sage.libs.giac`.
@@ -941,28 +999,48 @@ def __init__(self):
                              type='standard')
 
 
-class sage__rings__polynomial__pbori(JoinFeature):
+class sage__rings__polynomial__pbori(BuildFeature, PythonModule):
     r"""
     A :class:`sage.features.Feature` describing the presence of :mod:`sage.rings.polynomial.pbori`.
 
     TESTS::
 
         sage: from sage.features.sagemath import sage__rings__polynomial__pbori
-        sage: sage__rings__polynomial__pbori().is_present()                             # needs sage.rings.polynomial.pbori
+        sage: sage__rings__polynomial__pbori().is_present()  # needs sage.rings.polynomial.pbori
         FeatureTestResult('sage.rings.polynomial.pbori', True)
+
     """
+    _enabled_in_build = brial_enabled
+
     def __init__(self):
         r"""
         TESTS::
 
             sage: from sage.features.sagemath import sage__rings__polynomial__pbori
-            sage: isinstance(sage__rings__polynomial__pbori(), sage__rings__polynomial__pbori)
+            sage: isinstance(sage__rings__polynomial__pbori(),
+            ....:            sage__rings__polynomial__pbori)
             True
+
         """
-        JoinFeature.__init__(self, 'sage.rings.polynomial.pbori',
-                             [PythonModule('sage.rings.polynomial.pbori.pbori')],
-                             spkg='sagemath_brial', type='standard')
+        super().__init__('sage.rings.polynomial.pbori',
+                         spkg='sagemath_brial',
+                         type='standard')
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
 
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.sagemath import sage__rings__polynomial__pbori
+            sage: pbori = sage__rings__polynomial__pbori()
+            sage: result = pbori.is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs sage.rings.polynomial.pbori
+            FeatureTestResult('sage.rings.polynomial.pbori', True)
+
+        """
+        return PythonModule._is_present(self)
 
 class sage__rings__real_double(PythonModule):
     r"""
diff --git a/src/sage/features/sirocco.py b/src/sage/features/sirocco.py
index 727513f940f..587cbc65304 100644
--- a/src/sage/features/sirocco.py
+++ b/src/sage/features/sirocco.py
@@ -13,20 +13,24 @@
 #                  https://www.gnu.org/licenses/
 # *****************************************************************************
 
-from . import PythonModule
-from .join_feature import JoinFeature
+from sage.config import sirocco_enabled
+from sage.features import PythonModule
+from sage.features.build_feature import BuildFeature
 
-
-class Sirocco(JoinFeature):
+class Sirocco(BuildFeature):
     r"""
-    A :class:`~sage.features.Feature` which describes whether the :mod:`sage.libs.sirocco`
-    module is available in this installation of Sage.
+    A :class:`~sage.features.Feature` which describes whether the
+    :mod:`sage.libs.sirocco` module is available in this installation
+    of Sage.
 
     EXAMPLES::
 
         sage: from sage.features.sirocco import Sirocco
-        sage: Sirocco().require()  # optional - sirocco
+        sage: Sirocco().require()  # needs sirocco
+
     """
+    _enabled_in_build = sirocco_enabled
+
     def __init__(self):
         r"""
         TESTS::
@@ -34,11 +38,26 @@ def __init__(self):
             sage: from sage.features.sirocco import Sirocco
             sage: Sirocco()
             Feature('sirocco')
+
         """
-        JoinFeature.__init__(self, "sirocco",
-                             [PythonModule("sage.libs.sirocco",
-                                           spkg='sirocco')])
+        super().__init__("sirocco", spkg='sirocco')
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
 
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.sirocco import Sirocco
+            sage: result = Sirocco().is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs sirocco
+            FeatureTestResult('sirocco', True)
+
+        """
+        result = PythonModule("sage.libs.sirocco")._is_present()
+        result.feature = self
+        return result
 
 def all_features():
     return [Sirocco()]
diff --git a/src/sage/features/tdlib.py b/src/sage/features/tdlib.py
index b47f9d8db9d..e11848dc41f 100644
--- a/src/sage/features/tdlib.py
+++ b/src/sage/features/tdlib.py
@@ -12,14 +12,17 @@
 #                  https://www.gnu.org/licenses/
 # *****************************************************************************
 
-from . import PythonModule
-from .join_feature import JoinFeature
+from sage.config import tdlib_enabled
+from sage.features import PythonModule
+from sage.features.build_feature import BuildFeature
 
-
-class Tdlib(JoinFeature):
+class Tdlib(BuildFeature):
     r"""
-    A :class:`~sage.features.Feature` describing the presence of the SageMath interface to the :ref:`tdlib <spkg_tdlib>` library.
+    A :class:`~sage.features.Feature` describing the presence of
+    the SageMath interface to the :ref:`tdlib <spkg_tdlib>` library.
     """
+    _enabled_in_build = tdlib_enabled
+
     def __init__(self):
         r"""
         TESTS::
@@ -27,11 +30,27 @@ def __init__(self):
             sage: from sage.features.tdlib import Tdlib
             sage: isinstance(Tdlib(), Tdlib)
             True
+
         """
-        JoinFeature.__init__(self, 'tdlib',
-                             [PythonModule('sage.graphs.graph_decompositions.tdlib',
-                                           spkg='tdlib')])
+        super().__init__('tdlib', spkg='tdlib')
+
+    def is_present_at_runtime(self):
+        r"""
+        TESTS::
 
+            sage: from sage.features import FeatureTestResult
+            sage: from sage.features.tdlib import Tdlib
+            sage: result = Tdlib().is_present_at_runtime()
+            sage: isinstance(result, FeatureTestResult)
+            True
+            sage: result  # needs tdlib
+            FeatureTestResult('tdlib', True)
+
+        """
+        modname = "sage.graphs.graph_decompositions.tdlib"
+        result = PythonModule(modname)._is_present()
+        result.feature = self
+        return result
 
 def all_features():
     return [Tdlib()]
diff --git a/src/sage/graphs/graph_decompositions/meson.build b/src/sage/graphs/graph_decompositions/meson.build
index 06763ab1771..bfe106dc0d0 100644
--- a/src/sage/graphs/graph_decompositions/meson.build
+++ b/src/sage/graphs/graph_decompositions/meson.build
@@ -83,3 +83,7 @@ py.extension_module(
   dependencies: [py_dep, cysignals, tdlib],
 )
 
+# Record in the config file whether or not optional packages were
+# found, so that we don't have to look for them at runtime.
+conf_data.set10('RANKWIDTH_ENABLED', rw.found())
+conf_data.set10('TDLIB_ENABLED', tdlib.found())
diff --git a/src/sage/graphs/graph_decompositions/rankwidth.pyx b/src/sage/graphs/graph_decompositions/rankwidth.pyx
index f5714cd9387..e1092a200ee 100644
--- a/src/sage/graphs/graph_decompositions/rankwidth.pyx
+++ b/src/sage/graphs/graph_decompositions/rankwidth.pyx
@@ -46,6 +46,7 @@ i.e. singletons.
 
 ::
 
+    sage: # needs rankwidth
     sage: g = graphs.PetersenGraph()
     sage: rw, tree = g.rank_decomposition()
     sage: all(len(v)==1 for v in tree if tree.degree(v) == 1)
@@ -58,6 +59,7 @@ from the smaller of the two and its complement.
 
 ::
 
+    sage: # needs rankwidth
     sage: g = graphs.PetersenGraph()
     sage: rw, tree = g.rank_decomposition()
     sage: u = Set([8, 9, 3, 7])
@@ -80,6 +82,7 @@ from the smaller of the two and its complement.
 
 EXAMPLES::
 
+        sage: # needs rankwidth
         sage: g = graphs.PetersenGraph()
         sage: g.rank_decomposition()
         (3, Graph on 19 vertices)
@@ -137,6 +140,7 @@ def rank_decomposition(G, verbose=False, immutable=None):
 
     EXAMPLES::
 
+        sage: # needs rankwidth
         sage: from sage.graphs.graph_decompositions.rankwidth import rank_decomposition
         sage: g = graphs.PetersenGraph()
         sage: rank_decomposition(g)
@@ -144,6 +148,7 @@ def rank_decomposition(G, verbose=False, immutable=None):
 
     On more than 32 vertices::
 
+        sage: # needs rankwidth
         sage: g = graphs.RandomGNP(40, .5)
         sage: rank_decomposition(g)
         Traceback (most recent call last):
@@ -152,6 +157,7 @@ def rank_decomposition(G, verbose=False, immutable=None):
 
     The empty graph::
 
+        sage: # needs rankwidth
         sage: g = Graph()
         sage: rank_decomposition(g)
         (0, Graph on 0 vertices)
@@ -302,6 +308,7 @@ def mkgraph(int num_vertices):
 
     EXAMPLES::
 
+        sage: # needs rankwidth
         sage: from sage.graphs.graph_decompositions.rankwidth import rank_decomposition
         sage: g = graphs.PetersenGraph()
         sage: rank_decomposition(g)
diff --git a/src/sage/graphs/meson.build b/src/sage/graphs/meson.build
index fce249794c7..6ab180db024 100644
--- a/src/sage/graphs/meson.build
+++ b/src/sage/graphs/meson.build
@@ -177,6 +177,11 @@ py.extension_module(
   dependencies: [py_dep, cysignals, mcqd],
 )
 
+# Record in the config file whether or not optional packages were
+# found, so that we don't have to look for them at runtime.
+conf_data.set10('BLISS_ENABLED', bliss.found())
+conf_data.set10('MCQD_ENABLED', mcqd.found())
+
 subdir('base')
 subdir('generators')
 subdir('graph_decompositions')
diff --git a/src/sage/libs/coxeter3/meson.build b/src/sage/libs/coxeter3/meson.build
index caf5f30b535..af484dc98a2 100644
--- a/src/sage/libs/coxeter3/meson.build
+++ b/src/sage/libs/coxeter3/meson.build
@@ -25,3 +25,7 @@ foreach name, pyx : extension_data_cpp
     dependencies: [py_dep, cysignals, coxeter3],
   )
 endforeach
+
+# Record in the config file whether or not optional packages were
+# found, so that we don't have to look for them at runtime.
+conf_data.set10('COXETER3_ENABLED', coxeter3.found())
diff --git a/src/sage/libs/meson.build b/src/sage/libs/meson.build
index 923fd5416b2..5710553c74b 100644
--- a/src/sage/libs/meson.build
+++ b/src/sage/libs/meson.build
@@ -169,6 +169,11 @@ foreach name, pyx : extension_data_cpp
   )
 endforeach
 
+# Record in the config file whether or not optional packages were
+# found, so that we don't have to look for them at runtime.
+conf_data.set10('MEATAXE_ENABLED', mtx.found())
+conf_data.set10('SIROCCO_ENABLED', sirocco.found())
+
 subdir('arb')
 subdir('coxeter3')
 install_subdir('cremona', install_dir: sage_install_dir / 'libs')
diff --git a/src/sage/meson.build b/src/sage/meson.build
index d43e636a4e8..8682482bb58 100644
--- a/src/sage/meson.build
+++ b/src/sage/meson.build
@@ -173,6 +173,12 @@ configure_file(
   configuration: kernel_data,
 )
 
+# Record what build-time features (e.g. external package support) were
+# enabled or disabled, and whether or not we should defer detection to
+# runtime.
+conf_data.set10('DEFER_FEATURE_CHECKS', get_option('defer_feature_checks'))
+conf_data.set10('ECLIB_ENABLED', ec.found())
+
 # Write config file
 # Should be last so that subdir calls can modify the config data
 config_file = configure_file(
diff --git a/src/sage/rings/polynomial/pbori/meson.build b/src/sage/rings/polynomial/pbori/meson.build
index 3456379c864..f12a5a70273 100644
--- a/src/sage/rings/polynomial/pbori/meson.build
+++ b/src/sage/rings/polynomial/pbori/meson.build
@@ -62,3 +62,6 @@ foreach name, pyx : extension_data_cpp
   )
 endforeach
 
+# Record in the config file whether or not optional packages were
+# found, so that we don't have to look for them at runtime.
+conf_data.set10('BRIAL_ENABLED', brial.found() and brial_groebner.found())