diff --git a/Makefile.inc1 b/Makefile.inc1
index 8a8f8cd31029..f404eaaf2436 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -1132,7 +1132,8 @@ _lex=		usr.bin/lex
 .endif
 
 .if ${BOOTSTRAPPING} < 1000013
-_yacc=		usr.bin/yacc
+_yacc=		lib/liby \
+		usr.bin/yacc
 .endif
 
 .if ${BOOTSTRAPPING} < 1000026