Improve flex correctness.

util/opt/build.mk

@@ -11,7 +11,6 @@ $(call flex, $(OBJDIR)/$D, $D/scan.l)
 $(call dependson, $(OBJDIR)/$D/y.tab.h)
 
 $(call rawfile, $(LIBEM_DATA))
-$(call rawfile, -lfl)
 $(call cprogram, $(OBJDIR)/$D/mktab)
 
 endef

util/opt/mktab.y

@@ -294,6 +294,10 @@ main() {
 	return nerrors;
 }
 
+int yywrap(void) {
+	return 1;
+}
+
 yyerror(s) char *s; {
 
 	fprintf(stderr,"line %d: %s\n",lino,s);