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='2023-08-29 11:42:16 +0200'>2023-08-29</span></td><td><a href='/guix/commit/gnu/home/services/dict.scm?id=cf6abf50dbbbd95fef465ab4bb3b608843ac47e1'>home: services: dicod, syncthing: Import (gnu home services shepherd).</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://issues.guix.gnu.org/65510&gt;.

Without this import, 'shepherd-service-type' is not mapped, leading to
an error about missing 'system' target.

* gnu/home/services/dict.scm,
gnu/home/services/syncthing.scm: Add #:use-module clause.

Reported-by: Morgan Smith &lt;Morgan.J.Smith@outlook.com&gt;
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-08-20 22:48:47 +0200'>2023-08-20</span></td><td><a href='/guix/commit/gnu/home/services/dict.scm?id=1ce3424e22bc89e01f9cc3a2eb01232715495bd3'>home: services: Add dicod.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/home/services/dict.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* gnu/services/dict.scm (&lt;dicod-configuration&gt;)[home-service?]: New
field.
(dicod-shepherd-service): Do not map /dev/log when 'home-service?' is
true.  Remove 'user-processes' requirement when 'home-service?' is
true.
(dicod-shepherd-service): Set #:user and #:group to #f when
'home-service?' is true.
* doc/guix.texi (Miscellaneous Home Services): New node.
(Miscellaneous Services): Add cross-reference.
</span></span></td><td>Ludovic Courtès</td></tr>