Added filesystem to list of paths in porting README.
diff --git a/docs/README-porting.md b/docs/README-porting.md
index cf2d3ea..f13f83b 100644
--- a/docs/README-porting.md
+++ b/docs/README-porting.md
@@ -43,6 +43,7 @@ There are two basic ways of building SDL at the moment:
src/video/*.c
src/audio/disk/*.c
src/audio/dummy/*.c
+ src/filesystem/dummy/*.c
src/video/dummy/*.c
src/haptic/dummy/*.c
src/joystick/dummy/*.c