Problem: posix_memalign autoconf check broken on some platforms

Solution: import macro from autoconf-archive that works better
than AC_CHECK_FUNCS

configure.ac

@@ -19,6 +19,7 @@ m4_include([m4/ax_cxx_compile_stdcxx_11.m4])
 m4_include([m4/ax_code_coverage.m4])
 m4_include([m4/ax_valgrind_check.m4])
 m4_include([m4/ax_check_vscript.m4])
+m4_include([m4/ax_func_posix_memalign.m4])
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
 # This lets us use PACKAGE_VERSION in Makefiles
@@ -78,6 +79,7 @@ AC_LIBTOOL_WIN32_DLL
 AC_PROG_LIBTOOL
 AX_VALGRIND_CHECK
 AX_CHECK_VSCRIPT
+AX_FUNC_POSIX_MEMALIGN
 
 AC_ARG_ENABLE([force-CXX98-compat],
     [AS_HELP_STRING([--enable-force-CXX98-compat], [force C++98 build [default=disabled]])])
@@ -670,7 +672,7 @@ AC_LANG_POP([C++])
 
 # Checks for library functions.
 AC_TYPE_SIGNAL
-AC_CHECK_FUNCS(perror gettimeofday clock_gettime memset socket getifaddrs freeifaddrs fork posix_memalign mkdtemp accept4)
+AC_CHECK_FUNCS(perror gettimeofday clock_gettime memset socket getifaddrs freeifaddrs fork mkdtemp accept4)
 AC_CHECK_HEADERS([alloca.h])
 
 # pthread_setname is non-posix, and there are at least 4 different implementations

m4/ax_func_posix_memalign.m4

+# ===========================================================================
+#  https://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 9
+
+AC_DEFUN([AX_FUNC_POSIX_MEMALIGN],
+[AC_CACHE_CHECK([for working posix_memalign],
+  [ax_cv_func_posix_memalign_works],
+  [AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#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
+])