Meta: Port recent changes to the GN build

bc6eebb1d7713b66fca6ecfe098604862c766fd9

Meta/gn/secondary/Userland/Libraries/LibGfx/BUILD.gn

@@ -30,6 +30,7 @@ shared_library("LibGfx") {
     "AntiAliasingPainter.cpp",
     "Bitmap.cpp",
     "BitmapMixer.cpp",
+    "CMYKBitmap.cpp",
     "ClassicStylePainter.cpp",
     "ClassicWindowTheme.cpp",
     "Color.cpp",