Fix Windows build with WAF

vguimatsurface/wscript

@@ -27,12 +27,17 @@ def build(bld):
 		'Input.cpp',
 		'MatSystemSurface.cpp',
 		'asanstubs.cpp',
-		#'memorybitmap.cpp',						[$WIN32]
 		'TextureDictionary.cpp',
 		'../vgui2/src/vgui_key_translation.cpp',
 		'../public/vgui_controls/vgui_controls.cpp'
 	]
 
+	if bld.env.DEST_OS == 'win32':
+		source += [
+			'../public/tier0/memoverride.cpp',
+			'memorybitmap.cpp'
+		]
+
 	includes = [
 		'.',
 		'../public',
@@ -47,6 +52,8 @@ def build(bld):
 
 	if bld.env.DEST_OS == 'android':
 		libs += ['EXPAT']
+	elif bld.env.DEST_OS == 'win32':
+		libs += ['USER32', 'GDI32']
 
 	install_path = bld.env.LIBDIR