Add support for modular build structure. (#71)

This is part of the effort to make the Boost libraries "modular" for build and consumption. See https://lists.boost.org/Archives/boost/2024/01/255704.php and https://github.com/grafikrobot/boost-b2-modular/blob/b2-modular/README.adoc for more information.

This PR depends on the following other PRs being merged to both develop and master branches of the respective repos:

- boostorg/boost#854

build.jam

@@ -0,0 +1,36 @@
+# Copyright René Ferdinand Rivera Morell 2024
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+require-b2 5.2 ;
+
+constant boost_dependencies :
+    /boost/assert//boost_assert
+    /boost/config//boost_config
+    /boost/core//boost_core
+    /boost/filesystem//boost_filesystem
+    /boost/function//boost_function
+    /boost/move//boost_move
+    /boost/predef//boost_predef
+    /boost/smart_ptr//boost_smart_ptr
+    /boost/spirit//boost_spirit
+    /boost/system//boost_system
+    /boost/throw_exception//boost_throw_exception
+    /boost/type_index//boost_type_index
+    /boost/type_traits//boost_type_traits
+    /boost/winapi//boost_winapi ;
+
+project /boost/dll
+    : common-requirements
+        <include>include
+    ;
+
+explicit
+    [ alias boost_dll : : : : <library>$(boost_dependencies) ]
+    [ alias all : boost_dll test ]
+    ;
+
+call-if : boost-library dll
+    ;
+

test/Jamfile.v2

@@ -7,11 +7,15 @@
 
 # For more information, see http://www.boost.org
 
+require-b2 5.0.1 ;
+
+import-search /boost/config/checks ;
+
 # bring in rules for testing
 import testing ;
 import path ;
 
-import ../../config/checks/config : requires ;
+import config : requires ;
 
 local RDYNAMIC = <target-os>freebsd:<linkflags>"-rdynamic" <target-os>solaris:<linkflags>"-Bdynamic" <target-os>aix:<linkflags>"-rdynamic"
     <target-os>qnxnto,<toolset>qcc:<linkflags>"-Bdynamic" <target-os>qnxnto,<toolset>gcc:<linkflags>"-rdynamic"
@@ -20,13 +24,14 @@ local RDYNAMIC = <target-os>freebsd:<linkflags>"-rdynamic" <target-os>solaris:<l
 
 
 # Static library that is not linked with any of the boost libs
-lib static_plugin : ../example/tutorial4/static_plugin.cpp : <link>static <define>BOOST_SYSTEM_NO_DEPRECATED $(RDYNAMIC) ;
-lib static_refcounting_plugin : ../example/tutorial8/refcounting_plugin.cpp : <link>static <define>BOOST_SYSTEM_NO_DEPRECATED <variant>release $(RDYNAMIC) ;
+lib static_plugin : ../example/tutorial4/static_plugin.cpp : <link>static <define>BOOST_SYSTEM_NO_DEPRECATED $(RDYNAMIC) <library>/boost/dll//boost_dll ;
+lib static_refcounting_plugin : ../example/tutorial8/refcounting_plugin.cpp : <link>static <define>BOOST_SYSTEM_NO_DEPRECATED <variant>release $(RDYNAMIC) <library>/boost/dll//boost_dll ;
 
 
 project
    : source-location .
    : requirements
+      <library>/boost/dll//boost_dll
       [ requires cxx11_rvalue_references ]
       [ requires cxx11_static_assert ]
    # linux