m4/ax_save_flags_with_prefix.m4

# ==============================================================================
#  https://www.gnu.org/software/autoconf-archive/ax_save_flags_with_prefix.html
# ==============================================================================
#
# SYNOPSIS
#
#   AX_SAVE_FLAGS_WITH_PREFIX(PREFIX, LIST-OF-FLAGS)
#
# DESCRIPTION
#
#   For each flag in LIST-OF-FLAGS, it expands to lower-cased shell variable
#   with the prefix holding the flag original value.  The saved variables
#   can be restored by AX_RESTORE_FLAGS_WITH_PREFIX
#
#   As an example: AX_SAVE_FLAGS_WITH_PREFIX([GL], [[CFLAGS],[LIBS]])
#   expands to
#
#     gl_saved_flag_cflags="$CFLAGS"
#     gl_saved_flag_libs="$LIBS"
#     CFLAGS="$GL_CFLAGS $CFLAGS"
#     LIBS="$GL_LIBS $LIBS"
#
#   One common use case is to define a package specific wrapper macro around
#   this one, and also setup other variables if needed. For example:
#
#     AC_DEFUN([_AX_CHECK_GL_SAVE_FLAGS], [
#       AX_SAVE_FLAGS_WITH_PREFIX([GL],[$1])
#       AC_LANG_PUSH([C])
#     ])
#
#     # pushes GL_CFLAGS and GL_LIBS to CFLAGS and LIBS
#     # also set the current language to test to C
#     _AX_CHECK_GL_SAVE_FLAGS([[CFLAGS],[LIBS]])
#
# LICENSE
#
#   Copyright (c) 2016 Felix Chern <idryman@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 2 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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#   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
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#
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#   exception to the GPL to apply to your modified version as well.

#serial 3

AC_DEFUN([AX_SAVE_FLAGS_WITH_PREFIX],[
m4_ifval([$2], [
_ax_[]m4_tolower($1)_saved_flag_[]m4_tolower(m4_car($2))="$m4_car($2)"
m4_car($2)="$$1_[]m4_car($2) $m4_car($2)"
$0($1, m4_cdr($2))
])])