diff --git a/gdb/config/ultra3.mh b/gdb/config/ultra3.mh
index 1d345edb1b0..d7b227ffa05 100644
--- a/gdb/config/ultra3.mh
+++ b/gdb/config/ultra3.mh
@@ -1,6 +1,6 @@
 # Host: NYU Ultracomputer (AMD 29000 running Unix)
 CC=u3cc
-MUNCH_NM=u3nm
+MUNCH_DEFINE="MUNCH_NM=u3nm"
 XDEPFILES= ultra3-xdep.o infptrace.o
 XM_FILE= xm-ultra3.h
 XM_CFLAGS = -DSYM1