menuselect: Add libxml2 support (Patch 3)

This is the final patch in adding menuselect to Asterisk.
 - The first patch (r418832) added menuselect along with mxml
 - The second patch (r418833) removed mxml from menuselect

This patch adds support for libxml2 to menuselect, and makes libxml2 a
required library for Asterisk.

Note that the libxml2 portion of this patch was written by Sean Bright,
and was made available on a team branch:
  http://svn.digium.com/svn/menuselect/team/seanbright/libxml2/

Review: https://reviewboard.asterisk.org/r/3773/

ASTERISK-20703 #close
patches:
  some_mysterious_team_branch uploaded by seanbright (License 5060)



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@418834 65c4cc65-6c06-0410-ace0-fbb531ad65f3

menuselect/configure.ac

@@ -120,10 +120,19 @@ AC_CHECK_FUNCS([asprintf getloadavg setenv strcasestr strndup strnlen strsep uns
 AST_EXT_LIB_SETUP([NEWT], [newt], [newt])
 AST_EXT_LIB_SETUP([CURSES], [curses], [curses])
 AST_EXT_LIB_SETUP([NCURSES], [ncurses], [ncurses])
+AST_EXT_LIB_SETUP([LIBXML2], [LibXML2], [libxml2])
 
 AST_EXT_LIB_CHECK([NEWT], [newt], [newtBell], [newt.h])
 AST_EXT_LIB_CHECK([CURSES], [curses], [initscr], [curses.h])
 AST_EXT_LIB_CHECK([NCURSES], [ncurses], [initscr], [curses.h])
+AST_EXT_TOOL_CHECK([LIBXML2], [xml2-config], , ,
+        [#include <libxml/tree.h>
+        #include <libxml/parser.h>],
+        [LIBXML_TEST_VERSION])
+
+if test "${PBX_LIBXML2}" != 1; then
+  AC_MSG_ERROR([coult not find required 'Libxml2' development package])
+fi
 
 PBX_GTK2=0
 AC_CHECK_TOOL(PKGCONFIG, pkg-config, No)
@@ -140,7 +149,6 @@ AC_SUBST(GTK2_LIB)
 test "$silent"=yes && ac_sub_configure_args="${ac_sub_configure_args} --silent"
 
 AC_CONFIG_FILES([makeopts])
-AC_CONFIG_SUBDIRS([mxml])
 AC_OUTPUT
 
 AC_MSG_NOTICE(Menuselect build configuration successfully completed)