tools: generate most contents of library make variables

tools: generate most contents of library make variables

Library related make variables (CFLAGS_lib*, SHDEPS_lib*, LDLIBS_lib*
and SHLIB_lib*) mostly have a common pattern for their values. Generate
most of this content automatically by adding a new per-library variable
defining on which other libraries a lib is depending. Those definitions
are put into an own file in order to make it possible to include it
from various Makefiles, especially for stubdom.

This in turn makes it possible to drop the USELIB variable from each
library Makefile.

The LIBNAME variable can be dropped, too, as it can be derived from the
directory name the library is residing in.

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