-r1 breaks %option prefix="<...>" in the file, reverting back to 2.6.3 brings back all prefixes (and unbreaks compilation) that looks like this with -r1: conffile.yy.c:374:9: error: 'yywrap' macro redefined [-Werror,-Wmacro-redefined] #define yywrap(yyscanner) (/*CONSTCOND*/1) ^ conffile.yy.c:49:13: note: previous definition is here #define yywrap router_yywrap ^ (prefix=router_yy here)
this is fixed in 2.6.4