Making a Makefile respect custom CFLAGS
I assume this Makefile to work with any non-GNU make:
CFLAGS=`sdl-config --cflags` -Wall -Wextra
.PHONY: clean run
rm -f *.o tron
Now how would we fix this to respect custom CFLAGS (and LDFLAGS) in a
way that does not require GNU make (i.e. simply-expanded variables):
"[Recursively-expanded variables are] the only sort supported
by other versions of make". 
Any proposals for a generic solution that is upstream-suitable?
While the Makefile presented here is not likely to go into the tree I
had similar cases before so I felt like bringing this up. Thanks!