dnl Copyright (C) 2015 Free Software Foundation, Inc. dnl This file is free software, distributed under the terms of the GNU dnl General Public License. As a special exception to the GNU General dnl Public License, this file may be distributed as part of a program dnl that contains a configuration script generated by Autoconf, under dnl the same distribution terms as the rest of that program. # Define HAVE_BITFIELD_TYPE_MATTERS if the type of bitfields effects their # alignment. AC_DEFUN([gt_BITFIELD_TYPE_MATTERS], [ AC_CACHE_CHECK([if the type of bitfields matters], gt_cv_bitfield_type_matters, [ AC_TRY_COMPILE( [struct foo1 { char x; char y:1; char z; }; struct foo2 { char x; long long int y:1; char z; }; int foo1test[ sizeof (struct foo1) < sizeof (struct foo2) ? 1 : -1 ]; ], [], gt_cv_bitfield_type_matters=yes, gt_cv_bitfield_type_matters=no) ]) if test $gt_cv_bitfield_type_matters = yes; then AC_DEFINE(HAVE_BITFIELD_TYPE_MATTERS, 1, [Define if the type of bitfields effects alignment.]) fi ])