# ===========================================================================#      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],[dnlAC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_SET_IFAS_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