From 0692d02f5e04dede9a05f9bc3bac7bb6c91a9495 Mon Sep 17 00:00:00 2001
From: Hugh McMaster <hugh.mcmaster@outlook.com>
Date: Tue, 10 Mar 2020 21:33:45 +1100
Subject: [PATCH] Use PKG_CHECK_MODULES to find the libxml2 library

If pkg-config is not available, fall back to xml2-config.
---
 configure.in | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/configure.in b/configure.in
index 22f096a5ac..e74c0db6c6 100644
--- a/configure.in
+++ b/configure.in
@@ -927,15 +927,24 @@ PGAC_ARG_BOOL(with, libxml, no, [build with XML support],
               [AC_DEFINE([USE_LIBXML], 1, [Define to 1 to build with XML support. (--with-libxml)])])
 
 if test "$with_libxml" = yes ; then
-  PGAC_PATH_PROGS(XML2_CONFIG, xml2-config)
-  AC_ARG_VAR(XML2_CONFIG, [path to xml2-config utility])dnl
-  if test -n "$XML2_CONFIG"; then
-    for pgac_option in `$XML2_CONFIG --cflags`; do
+  PKG_CHECK_MODULES([XML2], [libxml-2.0 >= 2.6.23], [have_libxml2="yes"], [have_libxml2="no"])
+  if test "$have_libxml2" = "no"; then
+    PGAC_PATH_PROGS(XML2_CONFIG, xml2-config)
+    AC_ARG_VAR(XML2_CONFIG, [path to xml2-config utility])dnl
+    if test -n "$XML2_CONFIG"; then
+      XML2_CFLAGS=`$XML2_CONFIG --cflags`
+      XML2_LIBS=`$XML2_CONFIG --libs`
+      have_libxml2="yes"
+    fi
+  fi
+
+  if test "$have_libxml2" = "yes"; then
+    for pgac_option in "$XML2_CFLAGS"; do
       case $pgac_option in
         -I*|-D*) CPPFLAGS="$CPPFLAGS $pgac_option";;
       esac
     done
-    for pgac_option in `$XML2_CONFIG --libs`; do
+    for pgac_option in "$XML2_LIBS"; do
       case $pgac_option in
         -L*) LDFLAGS="$LDFLAGS $pgac_option";;
       esac
-- 
2.25.1