Add offsetof macro for those without it.

--HG--
branch : 1.7

diff --git a/missing.h b/missing.h
index cc7075fdb48277cc4f6502120413cba41a8516f8..7ddbaad2d11b728180fde75b3442721158111ad3 100644 (file)
--- a/missing.h
+++ b/missing.h
@@ -148,6 +148,17 @@
 # define MAX(a,b) (((a)>(b))?(a):(b))
 #endif
 
+/*
+ * Older systems may be missing stddef.h and/or offsetof macro
+ */
+#ifndef offsetof
+# ifdef __offsetof
+#  define offsetof(type, field) __offsetof(type, field)
+# else
+#  define offsetof(type, field) ((size_t)(&((type *)0)->field))
+# endif
+#endif
+
 /*
  * Simple isblank() macro and function for systems without it.
  */