Fix for building in release mode with scons.

Change given thumbs up from JesterKing.

source/blender/makesrna/intern/SConscript

@@ -101,6 +101,10 @@ if env['OURPLATFORM'] in ('win32-vc', 'win32-mingw', 'linuxcross', 'win64-vc'):
 if env['WITH_BF_INTERNATIONAL']:
     defs.append('WITH_INTERNATIONAL')
 
+if not env['BF_DEBUG']:
+    defs.append('NDEBUG')
+
+
 makesrna_tool.Append(CPPDEFINES=defs)
 
 makesrna_tool.Append (CPPPATH = Split(incs))