Don't use m4_include on relative file names, as it doesn't work.

Don't use m4_include on relative file names, as it doesn't work.
Remove obsolete references to bison.simple and bison.hairy.
* src/getargs.c (getargs) [MSDOS]: Don't assume optarg != NULL.
* src/parse-gram.y (declaration): Use enum "report_states".
* src/scan-skel.l ("@output ".*\n): Close any old yyout before new one.