st/xvmc: pick up the headers for distribution

- autotools/make will pick them up in the tarball.
 - Sort the list alphabetically.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

src/gallium/state_trackers/xvmc/Makefile.am

@@ -42,6 +42,8 @@ noinst_PROGRAMS = \
 	tests/test_blocks \
 	tests/test_rendering
 
+noinst_HEADERS = tests/testlib.h
+
 TEST_LIBS = $(XVMC_LIBS) -lXvMCW
 tests_test_context_SOURCES = tests/test_context.c tests/testlib.c
 tests_test_context_LDADD = $(TEST_LIBS)

src/gallium/state_trackers/xvmc/Makefile.sources

@@ -1,6 +1,7 @@
 C_SOURCES := \
+	attributes.c \
 	block.c \
-	surface.c \
 	context.c \
+	surface.c \
 	subpicture.c \
-	attributes.c
+	xvmc_private.h