scons: Use -static-libstdc++ on 32bits builds w/ Mingw-w64 too.
diff --git a/scons/gallium.py b/scons/gallium.py
index c3350b3..18be73f 100755
--- a/scons/gallium.py
+++ b/scons/gallium.py
@@ -540,7 +540,7 @@
         if env['platform'] == 'windows':
             # Avoid depending on gcc runtime DLLs
             linkflags += ['-static-libgcc']
-            if env['machine'] == 'x86_64':
+            if 'w64' in env['CC'].split('-'):
                 linkflags += ['-static-libstdc++']
             # Handle the @xx symbol munging of DLL exports
             shlinkflags += ['-Wl,--enable-stdcall-fixup']