SLAPI improvements (ITS#2073)

[ando@sys-net.it]

Steve,

now that I'm able to test the patch, I'm going to commit
it as soon as we fix some small problems and add a few
improvements.

Things like:
- libtool issues (as previously discussed: put libslapi in
  slapd and use -rdynamic where available, otherwise build
  a dynamic version of libslapi and let the modules load it);
- the possibility to set a path to search for when loading
  plugins; since in my commit SLPAI will use ltdl stuff,
  which is also used by dynamic modules, we might adapt the
  facilities provided for modules;
- the slapi error handling uses a mutex-protected file write;
  maybe we'd use syslog where available, and allow to set
  the file name/path, maybe on a plugin-basis, or simply
  use slapd's facilities.

Since the footprint of slapi on slapd's sources is quite
limited, we may delay further fixes, so that we get some
feedback from HEAD users.

Ando.

-- 
Pierangelo Masarati
mailto:pierangelo.masarati@sys-net.it