stddef: Add macro for member_size

Add macro to calculate size of a structure member

BUG=chrome-os-partner:41125
BRANCH=None
TEST=Compiles successfully

Change-Id: I71bcefe1c3b32ad559d7764e77369c67d09422a0
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: b425a310c14eabad79caf97649db6469380bd602
Original-Change-Id: I377fff062729aa664f7db469b86764b0ad941c38
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/276809
Original-Reviewed-by: Jimmy Zhang <jimmzhang@nvidia.com>
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Original-Trybot-Ready: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/10560
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
diff --git a/payloads/libpayload/include/stddef.h b/payloads/libpayload/include/stddef.h
index fca66ed..bb2971d 100644
--- a/payloads/libpayload/include/stddef.h
+++ b/payloads/libpayload/include/stddef.h
@@ -14,6 +14,7 @@
 #undef unsigned
 
 #define offsetof(TYPE, MEMBER)	((size_t) &((TYPE *) 0)->MEMBER)
+#define member_size(TYPE, MEMBER)	(sizeof(((TYPE *) 0)->MEMBER))
 
 /* Standard units. */
 #define KiB (1<<10)