diff --git a/mach/ns/libmon/head_em.s b/mach/ns/libmon/head_em.s
index f5135f7ef..9b4c9cebc 100644
--- a/mach/ns/libmon/head_em.s
+++ b/mach/ns/libmon/head_em.s
@@ -1,4 +1,5 @@
 .define hol0,argv,.reghp,.limhp,envp,begbss
+.define WRITE
 .define .ignmask, .trpreg
 .define .stop, BRK
 .define ERANGE,EILLINS,ECASE