From 6b08ad5263bc063c79666ffe2bd5ed9ab77a00a0 Mon Sep 17 00:00:00 2001
From: Paul Eggert
Date: Thu, 2 Nov 2017 13:06:38 -0700
Subject: Fix alignment portability problems

Do not assume that the natural alignment of Lisp objects is a
multiple of GCALIGNMENT.  This improves on the portability of the
recent fix for Bug#29040.
* lib-src/make-docfile.c (close_emacs_globals):
* src/buffer.c (buffer_defaults, buffer_local_symbols):
* src/lisp.h (DEFUN):
* src/thread.c (main_thread):
Use GCALIGNED, not alignas (GCALIGNMENT).
* src/alloc.c (COMMON_MULTIPLE):
Move back here from lisp.h, since it is no longer used elsewhere.
* src/lisp.h (GCALIGNMENT): No longer a macro, since we need not
worry about MSVC.  Omit no-longer-needed consistency check.
* src/thread.c (THREAD_ALIGNMENT): Remove.
---
 src/alloc.c | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'src/alloc.c')

diff --git a/src/alloc.c b/src/alloc.c
index ff93956109b..0fc79fe68ac 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -621,6 +621,12 @@ buffer_memory_full (ptrdiff_t nbytes)
 #endif
 }
 
+/* A common multiple of the positive integers A and B.  Ideally this
+   would be the least common multiple, but there's no way to do that
+   as a constant expression in C, so do the best that we can easily do.  */
+#define COMMON_MULTIPLE(a, b) \
+  ((a) % (b) == 0 ? (a) : (b) % (a) == 0 ? (b) : (a) * (b))
+
 #ifndef XMALLOC_OVERRUN_CHECK
 #define XMALLOC_OVERRUN_CHECK_OVERHEAD 0
 #else
-- 
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