clean Windows dependencies as well

Makefile

@@ -287,6 +287,7 @@ clean:
 	@-$(RM_F) *.exe *.dll ./OpenRA*/*.dll ./OpenRA*/*.mdb *.mdb mods/**/*.dll mods/**/*.mdb *.resources
 	@-$(RM_RF) ./*/bin ./*/obj
 	@-$(RM_F) ./thirdparty/*.dll
+	@-$(RM_RF) ./thirdparty/windows
 
 distclean: clean
 

make.ps1

@@ -71,8 +71,10 @@ elseif ($command -eq "clean")
 	else
 	{
 		$proc = Start-Process $msBuild $msBuildArguments -NoNewWindow -PassThru -Wait
-		rm *.dll # delete third party dependencies
+		rm *.dll
 		rm *.config
+		rm thirdparty/*.dll
+		rmdir thirdparty/windows/
 		rm mods/*/*.dll
 		echo "Clean complete."
 	}