diff --git a/src/frontend/parse.h b/src/frontend/parse.h
index 06ada8412..44aa3a544 100644
--- a/src/frontend/parse.h
+++ b/src/frontend/parse.h
@@ -11,7 +11,9 @@
 #include <wordlist.h>
 
 struct pnode * ft_getpnames(wordlist *wl, bool check);
+#ifndef free_pnode
 #define free_pnode(ptr)  free_pnode_x(ptr); ptr=NULL;
+#endif
 void free_pnode_x(struct pnode *t);