Add support for LOCAL_SRC_FILES_EXCLUDE

LOCAL_SRC_FILES_EXCLUDE will be used to filter files out of
LOCAL_SRC_FILES.  A common usage will be to use
LOCAL_SRC_FILES_EXCLUDE_<arch> to remove a source file that will be
replaced with an arch-optimized version.

Change-Id: I75cc6114c47fb784bab65cae8f618c4f395f07bb
2 files changed