RFC: static / dynamic linking in samba3

[Jeremy Allison]

On Thu, Apr 02, 2009 at 10:58:07AM +0200, Michael Adam wrote:
> I have just started to revise the s3-linking of internal subsystems
> as static vs. shared libraries.
> 
> As a first step, I have cleaned the SMB_LIBRARY mechanism so that
> I could remove the @LIBFOO_STATIC@ stuff from the object
> collections. (branches master / v3-4-test)
> This was based on a patch found in the debian packaging code.
> 
> There are a few items that are on my list next:
> 
> * I would like to unify the use of external libs:
>   Therefore I would like to rename the configure parameter
>   "--with-wbclient" to "--enable-external-libwbclient"
>   to be consistent with "--enable-external-talloc".
> 
>   Any objections?
> 
> * I would also like to (re-)unify the configuration of libwbclient
>   with the other libs (libtalloc, libtdb, libnetapi, ...) to be
>   configured with SMB_LIBRARY().
>   This means that it will also be possible again to build and link
>   libwbclient statically, removing the restriction imposed when
>   libsmbclient was originally created that it should only be
>   possible to build/link libwbclient statically with
>   --enable-develper. I think this is artificial. Sometimes you just
>   want to link a library statically. Vendors are patching the sources
>   to allow for building and linking statically anyways.
> 
> * Finally, I would come up with a linking scheme that copes
>   better with the fact that our libraries like libtalloc start to
>   appear as sytem libraries in the distributions (maybe triggered
>   by our introduction of building libtalloc and friends shared in
>   Samba 3.2).
> 
>   A scheme for building (that is basically also what samba4 does)
>   initially discussed with Jelmer and Lars (among others)
>   on irc could be the following:
> 
>   - check wheter libfoo is in the system
>     and check whether it suits our version requirements
>     (current checks use pkg-config for this)
> 
>   - if libfoo is available and version is ok, then
>     adapt compile / link flags according to pkg-config to
>     link against that library
> 
>   - if either the library is not found or version is not ok,
>     then build libfoo internally and link it in _statically_
> 
>   This would be the scheme for very isolated libraries like
>   libtalloc, libtdb.
> 
>   Other, more samba-specific subsystems that won't find their
>   way into distributions any time soon could still be built and
>   linked dynamically internally.
> 
> Folks, I would like to hear your comments on the suggestions above.

Sounds good to me. I agree on adding these to master so we
can monitor the progress.

Cheers,

Jeremy.