The definition of offsetof() uses size_t, which is declared in stddef.h, according to POSIX. Include stddef.h directly to avoid relying on implicit inclusion. Change-Id: I221be02c332de55c9fcf7d86673709ed43dd5c3c Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Reviewed-on: https://review.coreboot.org/22230 Reviewed-by: Aaron Durbin <adurbin@chromium.org> Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Maximilian Schander <coreboot@mimoja.de> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>