use local gtk folder if present when building Windows binary

setup_win32.py

@@ -20,9 +20,13 @@
 from distutils.core import setup
 import py2exe
 import glob
-import sys
+import sys
+import os
 
-sys.path.append('src')
+sys.path.append('src')
+# Use local gtk folder instead of the one in PATH that is not latest gtk
+if 'gtk' in os.listdir('.'):
+    sys.path.append('gtk/bin')
 includes = ['encodings', 'encodings.utf-8',]
 
 opts = {