scons: specialize CFLAGS for the only python cpp file that needs SVN_REVISION passed to it

SConstruct

@@ -331,6 +331,7 @@ pickle_store = [# Scons internal variables
         'PYTHON_SYS_PREFIX',
         'COLOR_PRINT',
         'HAS_BOOST_SYSTEM',
+        'SVN_REVISION'
         ]
 
 # Add all other user configurable options to pickle pickle_store
@@ -985,18 +986,11 @@ if not preconfigured:
         else :
             common_cxx_flags = '-D%s ' % env['PLATFORM'].upper()
 
-        
-        
-        if not env['FAST']:
-            # if we are in SCons FAST mode then make to 
-            # to avoid unnessary re-compiles due to changing
-            # CFLAGS when revision number increases 
         svn_version = call('svnversion')
         if not svn_version == 'exported':
             pattern = r'(\d+)(.*)'
             try:
-                    rev = re.match(pattern,svn_version).groups()[0]
-                    common_cxx_flags += '-DSVN_REVISION=%s ' % rev
+                env['SVN_REVISION'] = re.match(pattern,svn_version).groups()[0]
             except: pass
             
         # Mac OSX (Darwin) special settings

bindings/python/SConscript

@@ -137,6 +137,14 @@ env.Alias(target='install', source=ogcserver_module)
 
 
 # install the shared object beside the module directory
-_mapnik = env.LoadableModule('mapnik/_mapnik2', glob.glob('*.cpp'), LIBS=libraries, LDMODULEPREFIX='', LDMODULESUFFIX='.so', CPPPATH=headers,LINKFLAGS=linkflags)
+sources = glob.glob('*.cpp')
+
+if env.get('SVN_REVISION'):
+    sources.remove('mapnik_python.cpp')
+    env2 = env.Clone();
+    env2.Append(CCFLAGS='-DSVN_REVISION=%s' % env['SVN_REVISION'])
+    sources.insert(0,env2.Object('mapnik_python.cpp'))
+
+_mapnik = env.LoadableModule('mapnik/_mapnik2', sources, LIBS=libraries, LDMODULEPREFIX='', LDMODULESUFFIX='.so', CPPPATH=headers,LINKFLAGS=linkflags)
 pymapniklib = env.Install(env['PYTHON_INSTALL_LOCATION'] + '/mapnik2',_mapnik)
 env.Alias(target='install',source=pymapniklib)