parser: add some notes about byacc working We now also work with byacc (version tested: 20130925) which some people prefer, perhaps due to its license (public domain) or performance (haven't compared). When using byacc, currently the following warning comes up: src/xkbcomp/parser.c:954:14: warning: declaration shadows a variable in the global scope [-Wshadow] YYSTYPE yylval; ^ src/xkbcomp/parser.c:37:20: note: expanded from macro 'yylval' #define yylval _xkbcommon_lval ^ ./src/xkbcomp/parser.h:96:16: note: previous declaration is here extern YYSTYPE _xkbcommon_lval; This is due to a bug in byacc - it shouldn't output that extern line in %pure-parser mode. So the warning stays. Signed-off-by: Ran Benita <ran234@gmail.com>