tools/libxl: move libxenlight to tools/libs/light

Carve out all libxenlight related sources and move them to
tools/libs/light in order to use the generic library build environment.

The closely related sources for libxl-save-helper and the libxl test
environment are being moved, too.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wl@xen.org>

tools/configure.ac

@@ -4,7 +4,7 @@
 AC_PREREQ([2.67])
 AC_INIT([Xen Hypervisor Tools], m4_esyscmd([../version.sh ../xen/Makefile]),
     [xen-devel@lists.xen.org], [xen], [https://www.xen.org/])
-AC_CONFIG_SRCDIR([libxl/libxl.c])
+AC_CONFIG_SRCDIR([libs/light/libxl.c])
 AC_CONFIG_FILES([
 ../config/Tools.mk
 hotplug/FreeBSD/rc.d/xencommons