Problem reported by Herbert J. Skuhra in:
http://lists.gnu.org/archive/html/emacs-devel/2016-02/msg00354.html
Instead of trying
* src/alloc.c (lmalloc, lrealloc, laligned): New functions.
(xmalloc, xzalloc, xrealloc, lisp_malloc): Use them.
(__alignof__) [!__GNUC__ && !__alignof__]: New macro.
(MALLOC_IS_GC_ALIGNED): New macro.
* src/lisp.h (NONPOINTER_BITS): Remove. All uses removed.
No longer needed now that alloc.c uses lmalloc and lrealloc.