diff --git a/kconfig/zconf.gperf b/kconfig/zconf.gperf
index c9e690e..d758a2a 100644
--- a/kconfig/zconf.gperf
+++ b/kconfig/zconf.gperf
@@ -7,6 +7,15 @@
 %pic
 %struct-type

+%{
+# ifndef offsetof
+#  include <stddef.h>
+#  ifndef offsetof
+#   define offsetof(st, m) ((size_t)(&((st *)0)->m))
+#  endif
+# endif
+%}
+
 struct kconf_id;

 static struct kconf_id *kconf_id_lookup(register const char *str,