1# ===========================================================================
2#     https://www.gnu.org/software/autoconf-archive/ax_prepend_flag.html
3# ===========================================================================
4#
5# SYNOPSIS
6#
7#   AX_PREPEND_FLAG(FLAG, [FLAGS-VARIABLE])
8#
9# DESCRIPTION
10#
11#   FLAG is added to the front of the FLAGS-VARIABLE shell variable, with a
12#   space added in between.
13#
14#   If FLAGS-VARIABLE is not specified, the current language's flags (e.g.
15#   CFLAGS) is used.  FLAGS-VARIABLE is not changed if it already contains
16#   FLAG.  If FLAGS-VARIABLE is unset in the shell, it is set to exactly
17#   FLAG.
18#
19#   NOTE: Implementation based on AX_APPEND_FLAG.
20#
21# LICENSE
22#
23#   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
24#   Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
25#   Copyright (c) 2018 John Zaitseff <J.Zaitseff@zap.org.au>
26#
27#   Copying and distribution of this file, with or without modification, are
28#   permitted in any medium without royalty provided the copyright notice
29#   and this notice are preserved.  This file is offered as-is, without any
30#   warranty.
31
32#serial 2
33
34AC_DEFUN([AX_PREPEND_FLAG],
35[dnl
36AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_SET_IF
37AS_VAR_PUSHDEF([FLAGS], [m4_default($2,_AC_LANG_PREFIX[FLAGS])])
38AS_VAR_SET_IF(FLAGS,[
39  AS_CASE([" AS_VAR_GET(FLAGS) "],
40    [*" $1 "*], [AC_RUN_LOG([: FLAGS already contains $1])],
41    [
42     FLAGS="$1 $FLAGS"
43     AC_RUN_LOG([: FLAGS="$FLAGS"])
44    ])
45  ],
46  [
47  AS_VAR_SET(FLAGS,[$1])
48  AC_RUN_LOG([: FLAGS="$FLAGS"])
49  ])
50AS_VAR_POPDEF([FLAGS])dnl
51])dnl AX_PREPEND_FLAG
52