Re: Hack for inter-library dependency (make DESTDIR=... install) problem.

[roth . gnu]

==> "rb" == Rob Browning <address@hidden> writes:

    rb> address@hidden writes:
    >> Another solution (probably covered here) is to fill in the
    >> LIBRARY_PATH search path:
    >> 

    rb> Could you explain this a little further?  By LIBRARY_PATH here
    rb> do you mean LD_LIBRARY_PATH (at least for Linux)?

    rb> If so, I'm not sure this will help since the relink step
    rb> explicitly mentions -L/usr/lib -lfoo when I'm actually
    rb> installing into ./tmp via "make DESTDIR=`pwd`/tmp install",
    rb> and of course, foo's in pwd/tmp, not /usr/lib yet.

    rb> What I need is for the relink step to link against the build
    rb> tree libfoo (or more likely the DESTDIR libfoo) and not worry
    rb> about the fact that the library's eventually going to be in
    rb> /usr/lib...

The LIBRARY_PATH variable is what I meant.

The LD_LIBRARY_PATH variable is for ELF systems to find shared
libraries at run-time.  The LIBRARY_PATH variable, on the other hand,
is a gcc setting that lets it find libraries at link-time.  It's a
colon-separated path that fills in a bunch of '-L' options.  Other
linkers have similar extensions -- LPATH, LOPTS, etc.

If we fixup all of the .la files (such as by configuring to $DESTDIR),
then they'll be broken when the shared libraries are installed to
their final locations -- the $exec_prefix setting in the .la file
drives the -rpath switches during the relink.

What's desired here is to leave the .la files unchanged, but to add
some more link-time link paths (via -L switches).  If you don't want
to hack your Makefiles, you can trick the build process by exporting a
custom LIBRARY_PATH setting to the make process.  One could envision a
DESTDIR-aware libtool that would do this automatically.

I've used this trick successfully in building rpm's containing
multiple, interdependent shared libraries.  The spec file cooks up a
custom LIBRARY_PATH setting before invoking 'make DESTDIR=foo
install'.  The name of the game in spec file writing is to minimize
the patch set required to build the package, so Makefile hackery is
discouraged.

- C