Author: Reiner Herrmann <reiner@reiner-h.de>
Description: Sort source files to get a deterministic linking order

--- a/Makefile
+++ b/Makefile
@@ -124,7 +124,7 @@
 LDOPTS = $(GOAL_OPTS) $(LNK_LIBS)
 
 # source files in this project
-sources := $(wildcard $(srcdir)/*.$(SOURCE_SUFFIX))
+sources := $(sort $(wildcard $(srcdir)/*.$(SOURCE_SUFFIX)))
 
 # object files in this project
 objs := $(notdir $(sources))