Description: Honour PKG_CONFIG environment variable
 autoconf and several other build system respect the PKG_CONFIG environment
 variable. This is useful e.g. for cross-building, where the "correct"
 pkg-config/pkgconf binary should be used. Cf. from
 /usr/share/doc/pkgconf-bin/README.md.gz:
 .
  In  terms  of  the  autoconf macro, it is possible to specify the
  PKG_CONFIG environment variable, so that you can test pkgconf without
  overwriting your pkg‐config binary. Some other build systems may also
  respect the PKG_CONFIG environment variable.
 .
  To set the environment variable on the bourne  shell  and  clones
  (i.e. bash), you can run:
 .
    $ export PKG_CONFIG=/usr/bin/pkgconf
 .
 In Debian, PKG_CONFIG is already set and/or exported by dpkg
 (/usr/share/dpkg/buildtools.mk) and by debhelper's EUMM and MB build
 helpers.
 .
 This patch uses the value of PKG_CONFIG if it's set instead of the
 hard-coded `pkg-config`.
Origin: vendor
Bug: https://gitlab.gnome.org/GNOME/perl-extutils-pkgconfig/-/merge_requests/1
Forwarded: https://gitlab.gnome.org/GNOME/perl-extutils-pkgconfig/-/merge_requests/1
Author: gregor herrmann <gregoa@debian.org>
Last-Update: 2025-07-08

--- a/lib/ExtUtils/PkgConfig.pm
+++ b/lib/ExtUtils/PkgConfig.pm
@@ -26,6 +26,8 @@
 
 $VERSION = '1.16';
 
+my $pkg_config = $ENV{PKG_CONFIG} // 'pkg-config';
+
 sub import {
 	my $class = shift;
 	return unless @_;
@@ -53,16 +55,16 @@
 	                              libs-only-other/)
 	{
 		# simple
-		$ans = `pkg-config --$function \"$modulename\"`;
+		$ans = `$pkg_config --$function \"$modulename\"`;
 	}
 	elsif ('static-libs' eq $function)
 	{
-		$ans = `pkg-config --libs --static \"$modulename\"`;
+		$ans = `$pkg_config --libs --static \"$modulename\"`;
 	}
 	elsif ('variable' eq $function)
 	{
 		# variable
-		$ans = `pkg-config --${function}=$arg \"$modulename\"`;
+		$ans = `$pkg_config --${function}=$arg \"$modulename\"`;
 	}
 	elsif (grep {$_ eq $function} qw/atleast-version
 	                                 exact-version
@@ -70,7 +72,7 @@
 	{
 		# boolean
 		$ans = not system (
-			"pkg-config --${function}=$arg \"$modulename\"");
+			"$pkg_config --${function}=$arg \"$modulename\"");
 	}
 	else
 	{
@@ -89,7 +91,7 @@
 	
 	foreach my $candidate (@pkg_candidates)
 	{
-		my $output = qx/pkg-config --exists "$candidate" 2>&1/;
+		my $output = qx/$pkg_config --exists "$candidate" 2>&1/;
 		if (0 == $CHILD_ERROR) {
 			return 1;
 		}
@@ -106,7 +108,7 @@
 	# recognizes
 	foreach my $candidate (@pkg_candidates)
 	{
-		my $output = qx/pkg-config --exists --print-errors "$candidate" 2>&1/;
+		my $output = qx/$pkg_config --exists --print-errors "$candidate" 2>&1/;
 		if (0 == $CHILD_ERROR) {
 			push @pkgs_found, $candidate;
 		}
@@ -139,7 +141,7 @@
 	my %data = ();
 	$data{pkg} = $pkgs_found[0];
 	foreach my $what (qw/modversion cflags libs/) {
-		$data{$what} = `pkg-config --$what \"$data{pkg}\"`;
+		$data{$what} = `$pkg_config --$what \"$data{pkg}\"`;
                 $data{$what} =~ s/[\015\012]+$//;
 		croak "*** can't find $what for \"$data{pkg}\"\n"
 		    . "*** is it properly installed and available in PKG_CONFIG_PATH?\n"