Re: [Gimp-developer] GIMP looking for babl and GEGL outside the prefix

[Michael Natterer <mitch gimp org>]

On Mon, 2015-02-23 at 09:25 -0500, Elle Stone wrote:
> On 02/23/2015 07:11 AM, Michael Natterer wrote:
>
> > A more-or-less complete development
> > prefix environment looks like this (working example from my disk, with
> > all the same packages in prefix also installed by the OS in /usr):
> >
> > PREFIX=/home/elle/code/gimpdefault/run
> > export PATH=$PREFIX/bin:$PATH
> > export LD_LIBRARY_PATH=$PREFIX/lib:$LD_LIBRARY_PATH
> > export XDG_DATA_DIRS=$PREFIX/share:$XDG_DATA_DIRS
> > export ACLOCAL_FLAGS="-I $PREFIX/share/aclocal"
> > export PKG_CONFIG_PATH=$PREFIX/lib/pkgconfig:$PKG_CONFIG_PATH
> >
> > If you also build glib in that prefix, it needs to find
> > OS-installed modules. On debian unstable 64 bit this looks
> > like:
> >
> > export GIO_EXTRA_MODULES=/usr/lib/x86_64-linux-gnu/gio/modules
> >
> > but might be different depending on the distribution.
>
> Mitch, thanks! Following your setup worked perfectly.
>
> glib did complain that $PREFIX/share/aclocal didn't exist, so I created 
> the empty directory and then everything went smoothly, with GIMP and 
> glib both writing ".m4" files to the aclocal directory. From curiosity, 
> why didn't babl and GEGL also write ".m4" files?

The m4 macros are doing fancy stuff... Instead of simply doing

pkg-config --foo glib-2.0"

or its m4 version 

PKG_CHECK_MODULES(GLIB, glib-2.0 >= glib_required_version)

you would use:

AM_PATH_GLIB_2_0(...)

which does the above, and additionally does paranoia checks like
verifying that the lib and its headers belong together, that a
program can actually be compiled against that version, and whatnot.

It's "extra paranoia", useful, but not strictly needed.

> In case anyone else is running Gentoo, the path (at least for a pure 
> 64-bit build) is "/usr/lib/gio/modules".
>
> For the next person who encounters this problem, maybe a link to Mitch's 
> post could be added to 
> http://wiki.gimp.org/wiki/Hacking:Problems_and_solutions#GIMP_build_fails_for_missing_BABL_function?

Or maybe it should be part of the FAQ?

Alexandre? I think this could be useful.

Regards,
--Mitch