https://bugs.gentoo.org/604610

New flex seems to define yywrap even for non-yywrap lexers.
diff --git a/src/base/init/lexer.l.in b/src/base/init/lexer.l.in
index aeaa2e2..9e42ddf 100644
--- a/src/base/init/lexer.l.in
+++ b/src/base/init/lexer.l.in
@@ -810,7 +810,2 @@ static void enter_includefile(char * fname)
 
-
-#ifdef yywrap
-  error "yywrap defined elsewere, need our own one"
-#endif
-
 int yywrap(void)    /* this gets called at EOF of a parsed file */