diff --git a/tools/build/cross-build/include/common/pwd.h b/tools/build/cross-build/include/common/pwd.h
index 14abc7fcadf0..109119e9bfe3 100644
--- a/tools/build/cross-build/include/common/pwd.h
+++ b/tools/build/cross-build/include/common/pwd.h
@@ -41,6 +41,10 @@
 
 #define user_from_uid __nbcompat_user_from_uid
 
+#ifndef _PASSWORD_EFMT1
+#define	_PASSWORD_EFMT1		'_'	/* extended encryption format */
+#endif
+
 int pwcache_userdb(int (*a_setpassent)(int), void (*a_endpwent)(void),
     struct passwd *(*a_getpwnam)(const char *),
     struct passwd *(*a_getpwuid)(uid_t));