* m2-exp.y: Avoid using yytname[] which is a Bison-ism.
* expread.y, expread.tab.c: Remove. * parser-defs.h: New file with common declarations from expread.y. * c-exp.y: New file with the C parser from expread.y. * m2-exp.y: New file with the Modula-2 parser.