remove remaining references to porterduff



git-svn-id: http://skia.googlecode.com/svn/trunk@236 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/Makefile b/Makefile
index bb10843..cce996a 100644
--- a/Makefile
+++ b/Makefile
@@ -132,8 +132,8 @@
 
 ##############################################################################
 
-GM_SRCS := gmmain.cpp xfermodes.cpp gradients.cpp tilemodes.cpp
-GM_SRCS := $(addprefix gm/, $(GM_SRCS))
+include gm/gm_files.mk
+GM_SRCS := $(addprefix gm/, $(SOURCE))
 
 GM_OBJS := $(GM_SRCS:.cpp=.o)
 GM_OBJS := $(addprefix out/, $(GM_OBJS))