diff --git a/lib/sl/Makefile.am b/lib/sl/Makefile.am
index 152b86a33..1213d8c9d 100644
--- a/lib/sl/Makefile.am
+++ b/lib/sl/Makefile.am
@@ -8,7 +8,7 @@ endif
 
 AM_CPPFLAGS += $(ROKEN_RENAME)
 
-YFLAGS = -d
+YFLAGS = -d -o slc-gram.c
 LFLAGS = @FLEXNOUNPUTARGS@
 
 include_HEADERS = sl.h