diff --git a/cf/have-struct-field.m4 b/cf/have-struct-field.m4
index 25342de75..bb7bcefbc 100644
--- a/cf/have-struct-field.m4
+++ b/cf/have-struct-field.m4
@@ -7,9 +7,11 @@ dnl AC_HAVE_STRUCT_FIELD(struct, field, headers)
 AC_DEFUN([AC_HAVE_STRUCT_FIELD], [
 define(cache_val, translit(ac_cv_type_$1_$2, [A-Z ], [a-z_]))
 AC_CACHE_CHECK([for $2 in $1], cache_val,[
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[$3]],[[$1 x; x.$2]])],
-[cache_val=yes],
-[cache_val=no])])
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[$3]],
+	[[$1 x; memset(&x, 0, sizeof(x)); x.$2]])],
+	[cache_val=yes],
+	[cache_val=no])
+])
 if test "$cache_val" = yes; then
 	define(foo, translit(HAVE_$1_$2, [a-z ], [A-Z_]))
 	AC_DEFINE(foo, 1, [Define if $1 has field $2.])