[libxml2]Add libxml2 library

libxml2/libxml.m4

@@ -0,0 +1,16 @@
+dnl AM_PATH_XML2([MINIMUM-VERSION, [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]]])
+dnl Test for XML, and define XML_CPPFLAGS and XML_LIBS
+dnl
+dnl Deprecated and unmaintained. Use pkg-config or xslt-config.
+dnl
+AC_DEFUN([AM_PATH_XML2],[
+  m4_warn([obsolete], [AM_PATH_XML2 is deprecated, use PKG_CHECK_MODULES instead])
+  AC_REQUIRE([PKG_PROG_PKG_CONFIG])
+
+  verdep=ifelse([$1], [], [], [">= $1"])
+  PKG_CHECK_MODULES(XML, [libxml-2.0 $verdep], [$2], [$3])
+
+  XML_CPPFLAGS=$XML_CFLAGS
+  AC_SUBST(XML_CPPFLAGS)
+  AC_SUBST(XML_LIBS)
+])