See PR pending https://github.com/shlomif/perl-XML-LibXSLT/pull/9.patch
fix hardcoded pkg-config
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -41,8 +41,10 @@ if ( delete $config{NO_THREADS} ) {
 # https://rt.cpan.org/Public/Bug/Display.html?id=116461
 my $HAVE_USER_DEFINED = (defined($config{LIBS}) or defined($config{INC}) );
 
+my $pkg_config = $ENV{PKG_CONFIG} || 'pkg-config';
+
 unless ( $::is_Win32 ) { # cannot get config in W32
-    my $xsltcfg = "pkg-config libxslt";
+    my $xsltcfg = "$pkg_config libxslt";
     my $libprefix = $ENV{XSLTPREFIX} || $config{XSLTPREFIX};
 
     delete $config{XSLTPREFIX}; # delete if exists, otherwise MakeMaker gets confused
@@ -174,7 +176,7 @@ if (have_library($::is_Win32 ? "libexslt" : "exslt")) {
         my $exslt_defaults = $::is_Win32 ?
         ($ENV{ACTIVEPERL_MINGW} ? q/-llibexslt.lib/ : q/-llibexslt/) :
         q/-lexslt/; # -lgcrypt -lgpg-error/;
-        my $exsltcfg = 'pkg-config libexslt';
+        my $exsltcfg = "$pkg_config libexslt";
         my ($exslt_libs,$exslt_inc);
         eval {
             print "running $exsltcfg... ";