* c-exp.y, m2-exp.y: Migrate code that has nothing to do with

	* c-exp.y, m2-exp.y:  Migrate code that has nothing to do with
	expression parsing into c-lang.c and m2-lang.c respectively.
	* c-lang.c, m2-lang.c:  New files, code migrated from c-exp.y and
	m2-exp.y respectively.
	* c-lang.h, m2-lang.h:  New files, internal interfaces between c-*
	and m2-* files respectively.
	* Makefile.in (SFILES_MAINDIR):  Add c-lang.c, m2-lang.c.
	* Makefile.in (HFILES):  Add c-lang.h, m2-lang.h.
	* Makefile.in (OBS):  Add c-lang.o, m2-lang.o.
	* expression.h (struct block):  Forward declaration for prototypes.
	* language.h (struct objfile):  Forward declaration for prototypes.
	**** start-sanitize-chill ****
	* Makefile.in (SFILES_MAINDIR):  Add ch-lang.c.
	* Makefile.in (HFILES):  Add ch-lang.h.
	* Makefile.in (OBS):  Add ch-lang.o.
	* ch-exp.y:  Migrate code that has nothing to do with expression
	parsing into ch-lang.c.
	* ch-lang.c:  New file, code migrated from c-exp.y.
	* ch-lang.h:  New file, internal interface between ch-* files.
	**** end-sanitize-chill ****