rawhide report: 20060207 changes

[Ralf Corsepius]

On Tue, 2006-02-07 at 09:41 -0800, Toshio Kuratomi wrote:
> On Tue, 2006-02-07 at 07:22 -0500, Mike A. Harris wrote:
> > If a package wishes to retain build time compatibility with
> > X11R6 et al. it could use fallbacks if the pkg-config files
> > aren't present, however from here on out, using pkgconfig
> > is the very highly recommended way to detect the X libraries
> > and other bits and pieces.
> > 
> Where should this be implemented?
Inside of a package's configure script.

What Mike says, basically boils down to treat "X libs" as you would
handle other libraries.

The most simple but also most flexible approach would be to use
AC_CHECK_HEADERS/AC_CHECK_LIBS on each of the files being used by a
package. This essentially means shifting selection of directories/paths
to the user
(configure CPPFLAGS=-I/usr/X11R6/include LDFLAGS=-L/usr/X11R6/lib)

However, in practice, this is hardly applicable on X11 packages (It is
the reason why AC_PATH_X* exist) :(

>   Should AC_PATH_X/XTRA be changed to
> attempt to use pkgconfig as a first choice and then use AC_PATH_X if it
> isn't found?  (I don't know how autoconf deals with dependencies on
> optional m4 macros but for now I'm supposing this is possible)
Providing aclocal macros/wrappers around pkg-config is task of the
package providing the *.pc-file, i.e. each of those X11-libraries would
have to provide them (c.f. how gtk/gnome handles this).

> Or does every package using AC_PATH_X need to create the logic for using
> pkg-config with optional fallbacks to X11R6 behavior and then try to
> push those changes upstream (using autoconf/autoconf-patches until the
> changes are accepted and released.)
It depends. As I see it, you have 4 choices:

1. Use the old fsf-autoconf behavior: I.e. use AC_PATH_X* with the check
for Xt, and presume all X11 files to be installed to the same
directories. Rpm-wise, you'd have to "BR: libXt-devel" in all such
packages, and the behavior should be the same as it has been so far.

This would be the "short term and least invasive" approach.


2. Treat X11 libs as normal libs, and check for each file required
manually. Due to the number of libs being involved into X11 this is very
tedious and hardly possible. However, as long as all X11 libs are
installed to the same directories, the "sloppy method" of checking for a
subset of libs/headers and presuming other libs/headers to be pulled in
implicitly, often is sufficient.


3. Rely on the X11R7-packages providing appropriate *.pc files, and
abandon X11R6. Then using PKG_CHECK_MODULES(...) in configure scripts
should be sufficient. This is the most simple approach, but means
breaking backward compatibility.


4. Pragmatically combine 1-3. I'd expect combining 3 + 1 is what would
be the "common approach".

Ralf