Add an environment variable to python-sip that extends its search
directories for .sip files.

It seems that we cannot easily change the destination folder of these
files though, so this variable must be set on a per-package basis (and
non through search-path).

--- sip/sipbuild/builder.py	2023-03-22 09:06:37.588792878 +0100
+++ sip/sipbuild/builder.py	2023-03-22 09:10:35.830181134 +0100
@@ -254,6 +254,10 @@
                     os.path.join(project.target_dir,
                             project.get_bindings_dir()))
 
+            # Add extra bindings from environment for GNU Guix.
+            if 'SIP_INCLUDE_DIRS' in os.environ:
+                sip_include_dirs.extend(os.environ['SIP_INCLUDE_DIRS'].split(os.pathsep))
+
             # Generate the sip.h file for the shared sip module.
             copy_sip_h(abi_major_version, project.build_dir,
                     project.sip_module, version_info=project.version_info)
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<tr><td><span title='2022-11-02 15:52:19 +0100'>2022-11-02</span></td><td><a href='/guix/commit/gnu/installer/dump.scm?id=80387bc7c3966602800116f5be3893c3d3044a96'>installer: Add core dump support.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes: &lt;https://issues.guix.gnu.org/58733&gt;

* gnu/installer.scm (installer-program): Enable core dump generation.
* gnu/installer/dump.scm (%core-dump): New variable.
(prepare-dump): Copy the core dump file.
* gnu/installer/newt/welcome.scm (run-welcome-page): Propose to report an
installation that previously generated a core dump.
</span></span></td><td>Mathieu Othacehe</td></tr>