[libxml2] Correct the usage of LDFLAGS

[Daniel Veillard <veillard src gnome org>]

commit 40fd6d2a1b9dfc8ef5b428c9df7bdcb3398d6bd3
Author: Mattias Hansson <mattihn axis com>
Date:   Thu Jan 28 14:20:09 2016 +0100

    Correct the usage of LDFLAGS
    
    For https://bugzilla.gnome.org/show_bug.cgi?id=761252
    
    It is no longer necessary to save system LDFLAGS when checking
    lib specific LDFLAGS.

 configure.ac |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 03302d6..5ffa01f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -159,7 +159,7 @@ AC_ARG_WITH(readline,
   if test "$withval" != "no" -a "$withval" != "yes"; then
     RDL_DIR=$withval
     CPPFLAGS="${CPPFLAGS} -I$withval/include"
-    LIBS="${LIBS} -L$withval/lib"
+    LDFLAGS="${LDFLAGS} -L$withval/lib"
   fi
 ])
 AC_ARG_WITH(regexps,
@@ -195,7 +195,7 @@ AC_ARG_WITH(zlib,
   if test "$withval" != "no" -a "$withval" != "yes"; then
     Z_DIR=$withval
     CPPFLAGS="${CPPFLAGS} -I$withval/include"
-    LIBS="${LIBS} -L$withval/lib"
+    LDFLAGS="${LDFLAGS} -L$withval/lib"
   fi
 ])
 AC_ARG_WITH(lzma,
@@ -203,7 +203,7 @@ AC_ARG_WITH(lzma,
   if test "$withval" != "no" -a "$withval" != "yes"; then
     LZMA_DIR=$withval
     CPPFLAGS="${CPPFLAGS} -I$withval/include"
-    LIBS="${LIBS} -L$withval/lib"
+    LDFLAGS="${LDFLAGS} -L$withval/lib"
   fi
 ])
 AC_ARG_WITH(coverage,