[Tools] Add bsp_directory.

Add bsp_directory for PrepareModuleBuilding function and module building environment can parse rtconfig.h too.

tools/building.py

@@ -256,7 +256,7 @@ def PrepareBuilding(env, root_directory, has_libcpu=False, remove_components = [
 
     return objs
 
-def PrepareModuleBuilding(env, root_directory):
+def PrepareModuleBuilding(env, root_directory, bsp_directory):
     import rtconfig
 
     global Env
@@ -265,6 +265,14 @@ def PrepareModuleBuilding(env, root_directory):
     Env = env
     Rtt_Root = root_directory
 
+    # parse bsp rtconfig.h to get used component
+    PreProcessor = SCons.cpp.PreProcessor()
+    f = file(bsp_directory + '/rtconfig.h', 'r')
+    contents = f.read()
+    f.close()
+    PreProcessor.process_contents(contents)
+    BuildOptions = PreProcessor.cpp_namespace
+
     # add build/clean library option for library checking
     AddOption('--buildlib',
               dest='buildlib',