ax_append_compile_flags.m4

# ============================================================================
#  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/>.
#
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#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