spandsp/m4/ax_func_memmove.m4

# ===========================================================================
#     https://www.gnu.org/software/autoconf-archive/ax_func_memmove.html
# ===========================================================================
#
# SYNOPSIS
#
#   AX_FUNC_MEMMOVE
#
# DESCRIPTION
#
#   Checks for a memmove that can handle overlaps correctly. If no working
#   memmove is found, request a replacement and warn the user about it.
#
# LICENSE
#
#   Copyright (c) 2008 Ruediger Kuhlmann <info@ruediger-kuhlmann.de>
#
#   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 8

AU_ALIAS([AC_FUNC_MEMMOVE], [AX_FUNC_MEMMOVE])
AC_DEFUN([AX_FUNC_MEMMOVE],
[AC_CHECK_FUNCS(memmove)
AC_MSG_CHECKING(for working memmove)
AC_CACHE_VAL(ac_cv_have_working_memmove,
[AC_RUN_IFELSE([AC_LANG_SOURCE([[#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void)
{
    char buf[10];
    strcpy (buf, "01234567");
    memmove (buf, buf + 2, 3);
    if (strcmp (buf, "23434567"))
        exit (1);
    strcpy (buf, "01234567");
    memmove (buf + 2, buf, 3);
    if (strcmp (buf, "01012567"))
        exit (1);
    exit (0);
}]])],[ac_cv_have_working_memmove=yes],[ac_cv_have_working_memmove=no],[ac_cv_have_working_memmove=cross])])
AC_MSG_RESULT([$ac_cv_have_working_memmove])
if test x$ac_cv_have_working_memmove != "xyes"; then
  AC_LIBOBJ(memmove)
  AC_MSG_WARN([Replacing missing/broken memmove.])
  AC_DEFINE(PREFER_PORTABLE_MEMMOVE, 1, "enable replacement memmove if system memmove is broken or missing")
fi])