# ============================================================================#  https://www.gnu.org/software/autoconf-archive/ax_append_compile_flags.html# ============================================================================## SYNOPSIS##   AX_APPEND_COMPILE_FLAGS([FLAG1 FLAG2 ...], [FLAGS-VARIABLE], [EXTRA-FLAGS], [INPUT])## DESCRIPTION##   For every FLAG1, FLAG2 it is checked whether the compiler works with the#   flag.  If it does, the flag is added FLAGS-VARIABLE##   If FLAGS-VARIABLE is not specified, the current language's flags (e.g.#   CFLAGS) is used.  During the check the flag is always added to the#   current language's flags.##   If EXTRA-FLAGS is defined, it is added to the current language's default#   flags (e.g. CFLAGS) when the check is done.  The check is thus made with#   the flags: "CFLAGS EXTRA-FLAGS FLAG".  This can for example be used to#   force the compiler to issue an error when a bad flag is given.##   INPUT gives an alternative input source to AC_COMPILE_IFELSE.##   NOTE: This macro depends on the AX_APPEND_FLAG and#   AX_CHECK_COMPILE_FLAG. Please keep this macro in sync with#   AX_APPEND_LINK_FLAGS.## LICENSE##   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 6 AC_DEFUN([AX_APPEND_COMPILE_FLAGS],[AX_REQUIRE_DEFINED([AX_CHECK_COMPILE_FLAG])AX_REQUIRE_DEFINED([AX_APPEND_FLAG])for flag in $1; do  AX_CHECK_COMPILE_FLAG([$flag], [AX_APPEND_FLAG([$flag], [$2])], [], [$3], [$4])done])dnl AX_APPEND_COMPILE_FLAGS