"empty" Libtool libraries: supporting packages with multiple libraries

["Matthew D. Langston" <langston@SLAC.Stanford.EDU>]

I have successfully added GNU Autoconf, Automake and Libtool to a 3rd
party package, which is a collection of 28 C++ shared libraries.

However, it is hard for users to use these libraries because there are
so many of them.  Users continually either forget to add a few of these
libraries to the link line, or use them in the wrong order.  I am hoping
that Libtool's new Interlibrary dependency support have help me.

These libraries are used in 5 "sets", where each set is a subset of
these 28 shared libraries.  None of these sets intersect (e.g. each of
the 28 shared libraries belong to only one set).  Additionally, two of
these sets depend on "external" shared libraries.  Set 1 depends on
"-ldl" (or whatever the "dlopen" library is for the user's system),
while set 3 depends on the X11 + Xpm libraries.  Here is a table
describing this setup:

                              set 1  set 2  set 3  set 4  set 5
                              -----  -----  -----  -----  -----
shared libraries - internal:      1     19      4      1      3
shared libraries - external:      1      0      1      0      0

I would like to create a Libtool library for each set, so that a user
can simply add, e.g.  `.../set_4.la' to the link line.  In this example
(according to my table above), I would like for `.../set_4.la' to
"expand" into the 4 Libtool ".la" libraries in addition to the X11 + Xpm
libraries.

According to the Libtool 1.3 manual, interlibrary dependencies don't
currently work for Libtool libraries in the same package.  However, it
occurred to me that I could make another package that creates 5 "empty"
Libtool libraries (i.e. empty of ".lo" files), but contains only the
interlibrary dependency information.

Does this sound reasonable?  Does Libtool support these "empty" Libtool
libraries?  If so, how would I build them using Automake? Is there a
better way to solve my problem than attempting to create "empty" Libtool
libraries?

--
Matthew D. Langston
SLD, Stanford Linear Accelerator Center
langston@SLAC.Stanford.EDU