+# ===========================================================================
+# http://www.gnu.org/software/autoconf-archive/ax_func_posix_memalign.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+# AX_FUNC_POSIX_MEMALIGN
+#
+# DESCRIPTION
+#
+# Some versions of posix_memalign (notably glibc 2.2.5) incorrectly apply
+# their power-of-two check to the size argument, not the alignment
+# argument. AX_FUNC_POSIX_MEMALIGN defines HAVE_POSIX_MEMALIGN if the
+# power-of-two check is correctly applied to the alignment argument.
+#
+# LICENSE
+#
+# Copyright (c) 2008 Scott Pakin <pakin@uiuc.edu>
+#
+# Copying and distribution of this file, with or without modification, are
+# permitted in any medium without royalty provided the copyright notice
+# and this notice are preserved. This file is offered as-is, without any
+# warranty.
+
+#serial 7
+
+AC_DEFUN([AX_FUNC_POSIX_MEMALIGN],
+[AC_CACHE_CHECK([for working posix_memalign],
+ [ax_cv_func_posix_memalign_works],
+ [AC_TRY_RUN([
+#include <stdlib.h>
+
+int
+main ()
+{
+ void *buffer;
+
+ /* Some versions of glibc incorrectly perform the alignment check on
+ * the size word. */
+ exit (posix_memalign (&buffer, sizeof(void *), 123) != 0);
+}
+ ],
+ [ax_cv_func_posix_memalign_works=yes],
+ [ax_cv_func_posix_memalign_works=no],
+ [ax_cv_func_posix_memalign_works=no])])
+if test "$ax_cv_func_posix_memalign_works" = "yes" ; then
+ AC_DEFINE([HAVE_POSIX_MEMALIGN], [1],
+ [Define to 1 if `posix_memalign' works.])
+fi
+])