--- gobject-introspection-0cb6bd4db414d8dab7cc90d40faf577fcfd93198/giscanner/ccompiler.py.orig	2014-07-17 11:58:00.158239300 +0000
+++ gobject-introspection-0cb6bd4db414d8dab7cc90d40faf577fcfd93198/giscanner/ccompiler.py	2014-07-17 12:16:49.373631400 +0000
@@ -166,6 +166,11 @@
             macros.append(('_CRT_NONSTDC_NO_WARNINGS', None))
             macros.append(('SAL_NO_ATTRIBUTE_DECLARATIONS', None))
 
+        # customize_compiler from distutils only does customization
+        # for 'unix' compiler type
+        if self.compiler.compiler_type == 'mingw32' and self.compiler.preprocessor is None:
+          self.compiler.preprocessor = self.compiler.compiler + ["-E"]
+
         self.compiler.preprocess(source=source,
                                  output_file=output,
                                  macros=macros,
