Re: default $(libdir) and bi-arch systems

[Bob Friesenhahn]

On Wed, 10 Sep 2008, Bruno Haible wrote:

> > Right.  There is also value to separate between some libraries which
> > use the same ABI but with different run-time behavior.  For example,
> > libraries instrumented for profiling could go in a different
> > directory.
>
> Sure, there are several use-cases:
>  1) There are the 64/32 bit ABIs on Linux. By now this is probably affecting
>     the majority of the users of desktop x86 PCs.

Except that the majority of desktop x86 PCs are running Microsoft 
Windows. ;-)

>  2) There is the multilib support in gcc, as pointed out by Paolo and Ralf.
>  3) There is profiling and other variants.
>
> Case 1) has high priority IMO because it affects a large portion of the users
> who try the classical
>   ./configure
>   make
>   make install
> recipe and then discover that it does not produce working results.

Multilib support via libtool has been on the wish list for quite a 
while but implementing it is either a Big Job for libtool, or for the 
build environments which drive it.  It seems to me that if libtool 
supports the ability to build/install for an "offset" directory that 
the rest of the responsibility can fall into the hands of autoconf and 
automake.  There would need to be a configure framework which knows 
about the "standard" multilib conventions for each target and a build 
framework which builds all of them (or just the ones desired). Libtool 
is already complex enough so I think that most of the responsibility 
should be outside of libtool.  Libtool needs to know how to store 
multilib objects/libraries in the build tree (perhaps via a user 
provided 'tag') , and how to install the correct ones when requested.

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