Use pkg-config for libxml2 detection.

xml2-config does not work. Use pkgconfig to set CPPFLAGS and LIBS.

Upstream-Status: Inappropriate [configuration]

Signed-off-by:  Khem Raj <raj.khem@gmail.com>
---
 configure.in | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -2481,8 +2481,8 @@ AC_DEFUN([PHP_SETUP_LIBXML], [
     LIBXML_VERSION=`expr [$]1 \* 1000000 + [$]2 \* 1000 + [$]3`
     if test "$LIBXML_VERSION" -ge "2006011"; then
       found_libxml=yes
-      LIBXML_LIBS=`$XML2_CONFIG --libs`
-      LIBXML_INCS=`$XML2_CONFIG --cflags`
+      LIBXML_LIBS=`pkg-config --libs libxml-2.0`
+      LIBXML_INCS=`pkg-config --cflags libxml-2.0`
     else
       AC_MSG_ERROR([libxml2 version 2.6.11 or greater required.])
     fi