libltdl & Automake improvements

[Bob Friesenhahn]

Libtool 2.0 (in development) provides a libltdl build scheme which is 
intended to be integrated into the dependent package's configure/build 
rather than providing a separate configure script.  In this scheme 
"libltdl/Makefile" is added to the package's configure.ac AC_OUTPUT 
statement and the AC_LIB_LTDL macro is also added to configure.ac. 
The libltdl directory is added to the SUBDIRS definition.

Several recent Automake improvements may influence the 
preferred way to incorporate libltdl support:

  * Support for source files and targets in subdirectories.
  * Ability to avoid make recursion (related to above).
  * Makefile includes.

As of today, the main package I support uses a non-recursive Automake 
build and uses Automake includes.  The libltld used is an older one 
with just a few source files.  Rather than building libltdl as a 
"convenience" library the libltdl source files are simply incorporated 
into the package's main library.  If libltdl is to be installed, then 
it is built and used as a normal library.

Development libltdl now has a "complicated" Makefile.am which is using 
source files in subdirectories, and libltdl now includes quite a few 
source files rather than just two files.

It seems a shame that non-recursive packages must become recursive in 
order to build libltdl.  Using Automake includes, Automake 
conditionals, and well-defined conventions, libltdl's Makefile.am 
could simply be included into the package's own Makefile.am.  This 
would allow libltdl targets to be built without any additional 
recursion, and without creating another Makefile.in.

Thoughts?

Bob
======================================
Bob Friesenhahn
address@hidden
http://www.simplesystems.org/users/bfriesen