From 1a39781cff8614e155f9576fcf72b5706a1d1d31 Mon Sep 17 00:00:00 2001
From: Ivan Kravets <me@ikravets.com>
Date: Thu, 7 May 2015 18:13:29 +0100
Subject: [PATCH] Fix cancelling any previous definition of name, either built
 in or provided with a ``-D`` option // Resolve #191

---
 HISTORY.rst                            |  6 +++---
 platformio/builder/tools/platformio.py | 26 +++++++++++++++++++-------
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/HISTORY.rst b/HISTORY.rst
index d98e1a417e..9e71a5f896 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -4,9 +4,6 @@ Release History
 1.5.0 (2015-05-??)
 ------------------
 
-* Created `PlatformIO gitter.im <https://gitter.im/platformio/platformio>`_
-  room
-  (`issue #174 <https://github.com/platformio/platformio/issues/174>`_)
 * Added GDB as alternative uploader to `ststm32 <http://docs.platformio.org/en/latest/platforms/ststm32.html>`__ platform
   (`issue #175 <https://github.com/platformio/platformio/issues/174>`_)
 * Added `examples <https://github.com/platformio/platformio/tree/develop/examples>`__
@@ -14,6 +11,9 @@ Release History
   (`issue #154 <https://github.com/platformio/platformio/issues/154>`_)
 * Fixed parsing of includes for PlatformIO Library Dependency Finder
   (`issue #189 <https://github.com/platformio/platformio/issues/189>`_)
+* Fixed cancelling any previous definition of name, either built in or provided
+  with a ``-D`` option
+  (`issue #191 <https://github.com/platformio/platformio/issues/191>`_)
 
 1.4.0 (2015-04-11)
 ------------------
diff --git a/platformio/builder/tools/platformio.py b/platformio/builder/tools/platformio.py
index 9a7c4a51f3..a3c5aac940 100644
--- a/platformio/builder/tools/platformio.py
+++ b/platformio/builder/tools/platformio.py
@@ -15,18 +15,13 @@
 def BuildFirmware(env):
 
     # fix ASM handling under non-casitive OS
-    if not case_sensitive_suffixes('.s', '.S'):
+    if not case_sensitive_suffixes(".s", ".S"):
         env.Replace(
             AS="$CC",
             ASCOM="$ASPPCOM"
         )
 
-    if "extra_flags" in env.get("BOARD_OPTIONS", {}).get("build", {}):
-        env.MergeFlags(env.subst("${BOARD_OPTIONS['build']['extra_flags']}"))
-
-    if "BUILD_FLAGS" in env:
-        env.MergeFlags(env['BUILD_FLAGS'])
-
+    env.ProcessFlags()
     env.BuildFramework()
 
     firmenv = env.Clone()
@@ -69,6 +64,22 @@ def BuildFirmware(env):
     )
 
 
+def ProcessFlags(env):
+    if "extra_flags" in env.get("BOARD_OPTIONS", {}).get("build", {}):
+        env.MergeFlags(env.subst("${BOARD_OPTIONS['build']['extra_flags']}"))
+
+    if "BUILD_FLAGS" in env:
+        env.MergeFlags(env['BUILD_FLAGS'])
+
+    # Cancel any previous definition of name, either built in or
+    # provided with a -D option // Issue #191
+    undefines = [f for f in env.get("CCFLAGS", []) if f.startswith("-U")]
+    if undefines:
+        for undef in undefines:
+            env['CCFLAGS'].remove(undef)
+        env.Append(_CPPDEFFLAGS=" %s" % " ".join(undefines))
+
+
 def GlobCXXFiles(env, path):
     files = []
     for suff in ["*.c", "*.cpp", "*.S"]:
@@ -373,6 +384,7 @@ def exists(_):
 
 def generate(env):
     env.AddMethod(BuildFirmware)
+    env.AddMethod(ProcessFlags)
     env.AddMethod(GlobCXXFiles)
     env.AddMethod(VariantDirRecursive)
     env.AddMethod(BuildFramework)