diff --git a/src/cmd/idiff.c b/src/cmd/idiff.c
index 1dc49cff..c3168a2a 100644
--- a/src/cmd/idiff.c
+++ b/src/cmd/idiff.c
@@ -7,6 +7,8 @@
 #include <libc.h>
 #include <bio.h>
 
+#define opentemp idiffopentemp
+
 int diffbflag;
 int diffwflag;