[gobject-introspection] Check for MINGW instead of MINGW32

[Ignacio Casal Quinteiro <icq src gnome org>]

commit f530208ffe36f7f36476fd5f1bb78124cc9ac0ec
Author: Ignacio Casal Quinteiro <icq gnome org>
Date:   Wed Aug 6 11:00:59 2014 +0200

    Check for MINGW instead of MINGW32
    
    New versions of msys2 provide a MINGW64 env variable instead.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=734163

 giscanner/scannermain.py |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/giscanner/scannermain.py b/giscanner/scannermain.py
index ac34030..c3706f2 100755
--- a/giscanner/scannermain.py
+++ b/giscanner/scannermain.py
@@ -199,7 +199,8 @@ match the namespace prefix.""")
     group = get_preprocessor_option_group(parser)
     parser.add_option_group(group)
 
-    if os.environ.get('MSYSTEM') == 'MINGW32':
+    msystemenv = os.environ.get('MSYSTEM')
+    if msystemenv and msystemenv.startswith('MINGW'):
         group = get_windows_option_group(parser)
         parser.add_option_group(group)