From 3574ba6f1d5246384dd4582558fd520aeedb8b91 Mon Sep 17 00:00:00 2001
From: Paul Eggert <address@hidden>
Date: Wed, 29 Oct 2014 00:22:08 -0700
Subject: [PATCH 2/2] obstack: prefer alignof to calculating alignments by hand

* lib/obstack.c: Include <stdalign.h>.
(struct fooalign): Remove.
(DEFAULT_ALIGNMENT): Use alignof rather than the old offsetof hack.
* modules/obstack (Depends-on): Add stdalign.
---
 ChangeLog       | 8 ++++++++
 lib/obstack.c   | 8 ++------
 modules/obstack | 1 +
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 8bf2baa..ffe7285 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2014-10-29  Paul Eggert  <address@hidden>
+
+	obstack: prefer alignof to calculating alignments by hand
+	* lib/obstack.c: Include <stdalign.h>.
+	(struct fooalign): Remove.
+	(DEFAULT_ALIGNMENT): Use alignof rather than the old offsetof hack.
+	* modules/obstack (Depends-on): Add stdalign.
+
 2014-10-28  Paul Eggert  <address@hidden>
 
 	obstack: use size_t alignments and check for overflow
diff --git a/lib/obstack.c b/lib/obstack.c
index 342f9f8..03281ae 100644
--- a/lib/obstack.c
+++ b/lib/obstack.c
@@ -48,6 +48,7 @@
 #endif
 
 #ifndef _OBSTACK_ELIDE_CODE
+# include <stdalign.h>
 # include <stdlib.h>
 # include <stdint.h>
 
@@ -58,17 +59,12 @@ union fooround
   long double d;
   void *p;
 };
-struct fooalign
-{
-  char c;
-  union fooround u;
-};
 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
    But in fact it might be less smart and round addresses to as much as
    DEFAULT_ROUNDING.  So we prepare for it to do that.  */
 enum
 {
-  DEFAULT_ALIGNMENT = offsetof (struct fooalign, u),
+  DEFAULT_ALIGNMENT = alignof (union fooround),
   DEFAULT_ROUNDING = sizeof (union fooround)
 };
 
diff --git a/modules/obstack b/modules/obstack
index bceecdc..c2c6390 100644
--- a/modules/obstack
+++ b/modules/obstack
@@ -8,6 +8,7 @@ lib/obstack.c
 Depends-on:
 gettext-h
 exitfail
+stdalign
 stdint
 stdlib
 
-- 
1.9.3