* doc/bison.texinfo (-g, -x): Add space before argument.
(Option Cross Key): Implement FIXME: listing directives also.
* build-aux/cross-options.pl: Read from <STDIN> rather than <>.
(Short Option): Special case -d. Put arguments inside @option.
(Bison Directive): Add column, automatically extracted from
src/scan-gram.l (actual name passed as the first argument)
with special case for %define.
* doc/local.mk (doc/cross-options.texi): Pass src/scan-gram.l
to build-aux/cross-options.pl.
* src/getargs.c (usage): Document limitations of cross-options.pl.
* src/scan-gram.l: Likewise.
