The GNU coding standards specify that CFLAGS should be left for

The GNU coding standards specify that CFLAGS should be left for
	users to set.
	* Makefile.in (CFLAGS): Put this in the "things configure might
	edit" section, and have it default to -g.
	(ALL_CFLAGS): New variable, set to all the flags which should be
	passed to compilations.  Replace all other uses of CFLAGS with
	ALL_CFLAGS.
	(.c.o): New rule, to pass ALL_CFLAGS to compilations.

	* Makefile.in (DEFS): Remove this; it's always just going to be
	"-DHAVE_CONFIG_H -Demacs".

	* Makefile.in (ALLOCA): New variable, whose value we should
	inherit from the top-level makefile.
	(etags, ctags): Include ALLOCA in the list of object files that
	these executables depend on and link.