ref: 5f60997fe351d62b1eab9face1fbd9d51655aff3
dir: /m4/ax_append_flag.m4/
# ===========================================================================
# https://www.gnu.org/software/autoconf-archive/ax_append_flag.html
# ===========================================================================
#
# SYNOPSIS
#
# AX_APPEND_FLAG(FLAG, [FLAGS-VARIABLE])
#
# DESCRIPTION
#
# FLAG is appended to the FLAGS-VARIABLE shell variable, with a space
# added in between.
#
# If FLAGS-VARIABLE is not specified, the current language's flags (e.g.
# CFLAGS) is used. FLAGS-VARIABLE is not changed if it already contains
# FLAG. If FLAGS-VARIABLE is unset in the shell, it is set to exactly
# FLAG.
#
# NOTE: Implementation based on AX_CFLAGS_GCC_OPTION.
#
# LICENSE
#
# Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
# Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation, either version 3 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <https://www.gnu.org/licenses/>.
#
# As a special exception, the respective Autoconf Macro's copyright owner
# gives unlimited permission to copy, distribute and modify the configure
# scripts that are the output of Autoconf when processing the Macro. You
# need not follow the terms of the GNU General Public License when using
# or distributing such scripts, even though portions of the text of the
# Macro appear in them. The GNU General Public License (GPL) does govern
# all other use of the material that constitutes the Autoconf Macro.
#
# This special exception to the GPL applies to versions of the Autoconf
# Macro released by the Autoconf Archive. When you make and distribute a
# modified version of the Autoconf Macro, you may extend this special
# exception to the GPL to apply to your modified version as well.
#serial 7
AC_DEFUN([AX_APPEND_FLAG],
[dnl
AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_SET_IF
AS_VAR_PUSHDEF([FLAGS], [m4_default($2,_AC_LANG_PREFIX[FLAGS])])
AS_VAR_SET_IF(FLAGS,[
AS_CASE([" AS_VAR_GET(FLAGS) "],
[*" $1 "*], [AC_RUN_LOG([: FLAGS already contains $1])],
[
AS_VAR_APPEND(FLAGS,[" $1"])
AC_RUN_LOG([: FLAGS="$FLAGS"])
])
],
[
AS_VAR_SET(FLAGS,[$1])
AC_RUN_LOG([: FLAGS="$FLAGS"])
])
AS_VAR_POPDEF([FLAGS])dnl
])dnl AX_APPEND_FLAG