# ===========================================================================

# http://www.gnu.org/software/autoconf-archive/ax_add_fortify_source.html

# ===========================================================================

#

# SYNOPSIS

#

# AX_ADD_FORTIFY_SOURCE

#

# DESCRIPTION

#

# Check whether -D_FORTIFY_SOURCE=2 can be added to CPPFLAGS without macro

# redefinition warnings. Some distributions (such as Gentoo Linux) enable

# _FORTIFY_SOURCE globally in their compilers, leading to unnecessary

# warnings in the form of

#

# <command-line>:0:0: error: "_FORTIFY_SOURCE" redefined [-Werror]

# <built-in>: note: this is the location of the previous definition

#

# which is a problem if -Werror is enabled. This macro checks whether

# _FORTIFY_SOURCE is already defined, and if not, adds -D_FORTIFY_SOURCE=2

# to CPPFLAGS.

#

# LICENSE

#

# Copyright (c) 2017 David Seifert <soap@gentoo.org>

#

# 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 1

AC_DEFUN([AX_ADD_FORTIFY_SOURCE],[

AC_MSG_CHECKING([whether to add -D_FORTIFY_SOURCE=2 to CPPFLAGS])

AC_LINK_IFELSE([

AC_LANG_SOURCE(

[[

int main() {

#ifndef _FORTIFY_SOURCE

return 0;

#else

this_is_an_error;

#endif

}

]]

)], [

AC_MSG_RESULT([yes])

CPPFLAGS="$CPPFLAGS -D_FORTIFY_SOURCE=2"

], [

AC_MSG_RESULT([no])

])

])