michael@0: dnl This Source Code Form is subject to the terms of the Mozilla Public
michael@0: dnl dnl License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0: dnl dnl file, You can obtain one at http://mozilla.org/MPL/2.0/.
michael@0: 
michael@0: dnl Set of hotfixes to address issues in autoconf 2.13
michael@0: 
michael@0: dnl Divert AC_CHECK_FUNC so that the #includes it uses can't interfere
michael@0: dnl with the function it tests.
michael@0: dnl So, when testing e.g. posix_memalign, any #include that AC_CHECK_FUNC
michael@0: dnl prints is replaced with:
michael@0: dnl   #define posix_memalign innocuous_posix_memalign
michael@0: dnl   #include "theinclude"
michael@0: dnl   #undef posix_memalign
michael@0: dnl This avoids double declaration of that function when the header normally
michael@0: dnl declares it, while the test itself is just expecting the function not to be
michael@0: dnl declared at all, and declares it differently (which doesn't matter for the
michael@0: dnl test itself).
michael@0: dnl More recent versions of autoconf are essentially doing this.
michael@0: define([ac_cv_func_], [ac_cv_func2_])dnl
michael@0: define([_AC_CHECK_FUNC],defn([AC_CHECK_FUNC]))dnl
michael@0: define([AC_CHECK_FUNC], [dnl
michael@0: patsubst(_AC_CHECK_FUNC($@), [#include.*$], [#define $1 innocuous_$1
michael@0: \&
michael@0: #undef $1])])dnl