Fix build reproducibility in Make 3.82

Make 3.82 no longer sort the result of wildcards (see
http://comments.gmane.org/gmane.comp.gnu.make.bugs/4260). This may break
build reproducibility.

This patch sort results of wildcards to ensure reproducibility.

Signed-off-by: Jérôme Pouiller <jezz@sysmic.org>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
diff --git a/Makefile b/Makefile
index 0d7476a..3ca7313 100644
--- a/Makefile
+++ b/Makefile
@@ -333,7 +333,7 @@
 -include $(PACKAGE_OVERRIDE_FILE)
 endif
 
-include package/*/*.mk
+include $(sort $(wildcard package/*/*.mk))
 
 include boot/common.mk
 include linux/linux.mk