Update pkg.m4 to latest version

Upstream: https://gitlab.freedesktop.org/pkg-config/pkg-config/-/blob/master/pkg.m4.in

m4/pkg.m4

@@ -1,29 +1,60 @@
 # pkg.m4 - Macros to locate and utilise pkg-config.   -*- Autoconf -*-
-# serial 1 (pkg-config-0.24)
-#
-# Copyright © 2004 Scott James Remnant <scott@netsplit.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, write to the Free Software
-# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
-#
-# As a special exception to the GNU General Public License, if you
-# distribute this file as part of a program that contains a
-# configuration script generated by Autoconf, you may include it under
-# the same distribution terms that you use for the rest of that program.
-
-# PKG_PROG_PKG_CONFIG([MIN-VERSION])
-# ----------------------------------
+# serial 12 (pkg-config-0.29.2)
+
+dnl Copyright © 2004 Scott James Remnant <scott@netsplit.com>.
+dnl Copyright © 2012-2015 Dan Nicholson <dbn.lists@gmail.com>
+dnl
+dnl This program is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 2 of the License, or
+dnl (at your option) any later version.
+dnl
+dnl This program is distributed in the hope that it will be useful, but
+dnl WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+dnl General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program; if not, write to the Free Software
+dnl Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+dnl 02111-1307, USA.
+dnl
+dnl As a special exception to the GNU General Public License, if you
+dnl distribute this file as part of a program that contains a
+dnl configuration script generated by Autoconf, you may include it under
+dnl the same distribution terms that you use for the rest of that
+dnl program.
+
+dnl PKG_PREREQ(MIN-VERSION)
+dnl -----------------------
+dnl Since: 0.29
+dnl
+dnl Verify that the version of the pkg-config macros are at least
+dnl MIN-VERSION. Unlike PKG_PROG_PKG_CONFIG, which checks the user's
+dnl installed version of pkg-config, this checks the developer's version
+dnl of pkg.m4 when generating configure.
+dnl
+dnl To ensure that this macro is defined, also add:
+dnl m4_ifndef([PKG_PREREQ],
+dnl     [m4_fatal([must install pkg-config 0.29 or later before running autoconf/autogen])])
+dnl
+dnl See the "Since" comment for each macro you use to see what version
+dnl of the macros you require.
+m4_defun([PKG_PREREQ],
+[m4_define([PKG_MACROS_VERSION], [0.29.2])
+m4_if(m4_version_compare(PKG_MACROS_VERSION, [$1]), -1,
+    [m4_fatal([pkg.m4 version $1 or higher is required but ]PKG_MACROS_VERSION[ found])])
+])dnl PKG_PREREQ
+
+dnl PKG_PROG_PKG_CONFIG([MIN-VERSION])
+dnl ----------------------------------
+dnl Since: 0.16
+dnl
+dnl Search for the pkg-config tool and set the PKG_CONFIG variable to
+dnl first found in the path. Checks that the version of pkg-config found
+dnl is at least MIN-VERSION. If MIN-VERSION is not specified, 0.9.0 is
+dnl used since that's the first version where most current features of
+dnl pkg-config existed.
 AC_DEFUN([PKG_PROG_PKG_CONFIG],
 [m4_pattern_forbid([^_?PKG_[A-Z_]+$])
 m4_pattern_allow([^PKG_CONFIG(_(PATH|LIBDIR|SYSROOT_DIR|ALLOW_SYSTEM_(CFLAGS|LIBS)))?$])
@@ -45,18 +76,19 @@ if test -n "$PKG_CONFIG"; then
 		PKG_CONFIG=""
 	fi
 fi[]dnl
-])# PKG_PROG_PKG_CONFIG
-
-# PKG_CHECK_EXISTS(MODULES, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
-#
-# Check to see whether a particular set of modules exists.  Similar
-# to PKG_CHECK_MODULES(), but does not set variables or print errors.
-#
-# Please remember that m4 expands AC_REQUIRE([PKG_PROG_PKG_CONFIG])
-# only at the first occurence in configure.ac, so if the first place
-# it's called might be skipped (such as if it is within an "if", you
-# have to call PKG_CHECK_EXISTS manually
-# --------------------------------------------------------------
+])dnl PKG_PROG_PKG_CONFIG
+
+dnl PKG_CHECK_EXISTS(MODULES, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+dnl -------------------------------------------------------------------
+dnl Since: 0.18
+dnl
+dnl Check to see whether a particular set of modules exists. Similar to
+dnl PKG_CHECK_MODULES(), but does not set variables or print errors.
+dnl
+dnl Please remember that m4 expands AC_REQUIRE([PKG_PROG_PKG_CONFIG])
+dnl only at the first occurence in configure.ac, so if the first place
+dnl it's called might be skipped (such as if it is within an "if", you
+dnl have to call PKG_CHECK_EXISTS manually
 AC_DEFUN([PKG_CHECK_EXISTS],
 [AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
 if test -n "$PKG_CONFIG" && \
@@ -66,8 +98,10 @@ m4_ifvaln([$3], [else
   $3])dnl
 fi])
 
-# _PKG_CONFIG([VARIABLE], [COMMAND], [MODULES])
-# ---------------------------------------------
+dnl _PKG_CONFIG([VARIABLE], [COMMAND], [MODULES])
+dnl ---------------------------------------------
+dnl Internal wrapper calling pkg-config via PKG_CONFIG and setting
+dnl pkg_failed based on the result.
 m4_define([_PKG_CONFIG],
 [if test -n "$$1"; then
     pkg_cv_[]$1="$$1"
@@ -79,10 +113,11 @@ m4_define([_PKG_CONFIG],
  else
     pkg_failed=untried
 fi[]dnl
-])# _PKG_CONFIG
+])dnl _PKG_CONFIG
 
-# _PKG_SHORT_ERRORS_SUPPORTED
-# -----------------------------
+dnl _PKG_SHORT_ERRORS_SUPPORTED
+dnl ---------------------------
+dnl Internal check to see if pkg-config supports short errors.
 AC_DEFUN([_PKG_SHORT_ERRORS_SUPPORTED],
 [AC_REQUIRE([PKG_PROG_PKG_CONFIG])
 if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
@@ -90,26 +125,24 @@ if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
 else
         _pkg_short_errors_supported=no
 fi[]dnl
-])# _PKG_SHORT_ERRORS_SUPPORTED
-
-
-# PKG_CHECK_MODULES(VARIABLE-PREFIX, MODULES, [ACTION-IF-FOUND],
-# [ACTION-IF-NOT-FOUND])
-#
-#
-# Note that if there is a possibility the first call to
-# PKG_CHECK_MODULES might not happen, you should be sure to include an
-# explicit call to PKG_PROG_PKG_CONFIG in your configure.ac
-#
-#
-# --------------------------------------------------------------
+])dnl _PKG_SHORT_ERRORS_SUPPORTED
+
+
+dnl PKG_CHECK_MODULES(VARIABLE-PREFIX, MODULES, [ACTION-IF-FOUND],
+dnl   [ACTION-IF-NOT-FOUND])
+dnl --------------------------------------------------------------
+dnl Since: 0.4.0
+dnl
+dnl Note that if there is a possibility the first call to
+dnl PKG_CHECK_MODULES might not happen, you should be sure to include an
+dnl explicit call to PKG_PROG_PKG_CONFIG in your configure.ac
 AC_DEFUN([PKG_CHECK_MODULES],
 [AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
 AC_ARG_VAR([$1][_CFLAGS], [C compiler flags for $1, overriding pkg-config])dnl
 AC_ARG_VAR([$1][_LIBS], [linker flags for $1, overriding pkg-config])dnl
 
 pkg_failed=no
-AC_MSG_CHECKING([for $1])
+AC_MSG_CHECKING([for $2])
 
 _PKG_CONFIG([$1][_CFLAGS], [cflags], [$2])
 _PKG_CONFIG([$1][_LIBS], [libs], [$2])
@@ -156,16 +189,40 @@ else
         AC_MSG_RESULT([yes])
 	$3
 fi[]dnl
-])# PKG_CHECK_MODULES
+])dnl PKG_CHECK_MODULES
+
+
+dnl PKG_CHECK_MODULES_STATIC(VARIABLE-PREFIX, MODULES, [ACTION-IF-FOUND],
+dnl   [ACTION-IF-NOT-FOUND])
+dnl ---------------------------------------------------------------------
+dnl Since: 0.29
+dnl
+dnl Checks for existence of MODULES and gathers its build flags with
+dnl static libraries enabled. Sets VARIABLE-PREFIX_CFLAGS from --cflags
+dnl and VARIABLE-PREFIX_LIBS from --libs.
+dnl
+dnl Note that if there is a possibility the first call to
+dnl PKG_CHECK_MODULES_STATIC might not happen, you should be sure to
+dnl include an explicit call to PKG_PROG_PKG_CONFIG in your
+dnl configure.ac.
+AC_DEFUN([PKG_CHECK_MODULES_STATIC],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
+_save_PKG_CONFIG=$PKG_CONFIG
+PKG_CONFIG="$PKG_CONFIG --static"
+PKG_CHECK_MODULES($@)
+PKG_CONFIG=$_save_PKG_CONFIG[]dnl
+])dnl PKG_CHECK_MODULES_STATIC
 
 
-# PKG_INSTALLDIR(DIRECTORY)
-# -------------------------
-# Substitutes the variable pkgconfigdir as the location where a module
-# should install pkg-config .pc files. By default the directory is
-# $libdir/pkgconfig, but the default can be changed by passing
-# DIRECTORY. The user can override through the --with-pkgconfigdir
-# parameter.
+dnl PKG_INSTALLDIR([DIRECTORY])
+dnl -------------------------
+dnl Since: 0.27
+dnl
+dnl Substitutes the variable pkgconfigdir as the location where a module
+dnl should install pkg-config .pc files. By default the directory is
+dnl $libdir/pkgconfig, but the default can be changed by passing
+dnl DIRECTORY. The user can override through the --with-pkgconfigdir
+dnl parameter.
 AC_DEFUN([PKG_INSTALLDIR],
 [m4_pushdef([pkg_default], [m4_default([$1], ['${libdir}/pkgconfig'])])
 m4_pushdef([pkg_description],
@@ -179,13 +236,15 @@ m4_popdef([pkg_description])
 ])dnl PKG_INSTALLDIR
 
 
-# PKG_NOARCH_INSTALLDIR(DIRECTORY)
-# -------------------------
-# Substitutes the variable noarch_pkgconfigdir as the location where a
-# module should install arch-independent pkg-config .pc files. By
-# default the directory is $datadir/pkgconfig, but the default can be
-# changed by passing DIRECTORY. The user can override through the
-# --with-noarch-pkgconfigdir parameter.
+dnl PKG_NOARCH_INSTALLDIR([DIRECTORY])
+dnl --------------------------------
+dnl Since: 0.27
+dnl
+dnl Substitutes the variable noarch_pkgconfigdir as the location where a
+dnl module should install arch-independent pkg-config .pc files. By
+dnl default the directory is $datadir/pkgconfig, but the default can be
+dnl changed by passing DIRECTORY. The user can override through the
+dnl --with-noarch-pkgconfigdir parameter.
 AC_DEFUN([PKG_NOARCH_INSTALLDIR],
 [m4_pushdef([pkg_default], [m4_default([$1], ['${datadir}/pkgconfig'])])
 m4_pushdef([pkg_description],
@@ -199,10 +258,12 @@ m4_popdef([pkg_description])
 ])dnl PKG_NOARCH_INSTALLDIR
 
 
-# PKG_CHECK_VAR(VARIABLE, MODULE, CONFIG-VARIABLE,
-# [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
-# -------------------------------------------
-# Retrieves the value of the pkg-config variable for the given module.
+dnl PKG_CHECK_VAR(VARIABLE, MODULE, CONFIG-VARIABLE,
+dnl [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+dnl -------------------------------------------
+dnl Since: 0.28
+dnl
+dnl Retrieves the value of the pkg-config variable for the given module.
 AC_DEFUN([PKG_CHECK_VAR],
 [AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
 AC_ARG_VAR([$1], [value of $3 for $2, overriding pkg-config])dnl
@@ -211,4 +272,4 @@ _PKG_CONFIG([$1], [variable="][$3]["], [$2])
 AS_VAR_COPY([$1], [pkg_cv_][$1])
 
 AS_VAR_IF([$1], [""], [$5], [$4])dnl
-])# PKG_CHECK_VAR
+])dnl PKG_CHECK_VAR