Disabling use of ".la" files when linking ?

[Yvan FOURNIER]

Hello,

I would like to know if it is possible
to disable libtool's tracking of ".la" files (I found nothing
in the documentation or on the web).

The rationale is the following :

In an autoconf context, compile and
link tests for various libraries are done before libtool is used, and thus
do not
use the info available in .la files.
Once we have determined all the correct flags for external libraries, the
main benefit
of .la files (tracking dependencies
automatically) seems to be lost/unused.

In quite a few cases, the info in .la
files leads to problems. This occurs when:

- A library was moved (I know this shouldn't
be done, but when somebody already installed a library which is a pain
to install
on a given architecture, such as HDF5
on an IBM Blue Gene/P, and they are not available for the correction, being
able to ignore
.la files would be nice)

- A different compiler was used for
two libraries; this happens for example with OpenMPI 1.3 built with gcc,
which adds a
"-pthread" option in its .la
files. Trying to configure/compile/link a code using this under autotools
with a PGI compiler
leads to a link error as "-pthread"
is not recognized. This could be considered an issue with the upstream
library
not taking the required precautions
and using a "-Wl,..." type option instead, but I have seen nothing
in the libtool documentation
warning against such issues. Here again,
ignoring .la files would be useful.

- A similar example also occured in
a packaged GNU/Linux distribution (Ubuntu 9.04) with OpenMPI: the .la files
included
a "-liverbs" option, while
"libvierbs" is optional, loaded in a "plugin" type
manner, and not installed by default. Here again,
the link failed due to the .la files,
while configure had done fine.

- Finally, on a Blue Gene/P machine
(cross-compiling environment with a mix of static and shared libraries),
adding
a few C++ dependency libray options
led libtool to add other libraries from the front-end machine instead of
the target
machine, and the link failed also.

So basically, it would be nice to be
able to use libtool's handling of static or shared library functionnality
(i.e.
--enable/disable-shared/static in configure
options, having executables built in .libs with a wrapper having
the appropriate LD_LIBRARY_PATH options
to work pre-install, linking and possibly re-linking with the appropriate
rpath
command when compiling/installing, etc.),
but disable it's use of .la files.

An option similar to disable-shared
(perhaps "ignore-la" to ignore, "disable-la" to not
generate) that could also be
set through the autoconf LT_INIT macro
would thus be welcome.

Ideally, rpath info could in addition
be determined directly from library paths so as to keep libtool's rpath
handling
(one of its strong points IMHO), even
when not using .la files.

Best regards,

        Yvan
Fournier


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