Use gcc as the default C compiler if CC is not set.

diff -ru gobject-introspection-1.58.1.orig/giscanner/__init__.py gobject-introspection-1.58.1/giscanner/__init__.py
--- gobject-introspection-1.58.1.orig/giscanner/__init__.py	1970-01-01 01:00:00.000000000 +0100
+++ gobject-introspection-1.58.1/giscanner/__init__.py	2018-12-03 13:33:28.788971299 +0100
@@ -22,6 +22,8 @@
 builddir = os.environ.get('UNINSTALLED_INTROSPECTION_BUILDDIR')
 if builddir is not None:
     __path__.append(os.path.join(builddir, 'giscanner'))
+if not 'CC' in os.environ:
+    os.environ['CC'] = 'gcc'
 try:
     from ._version import __version__
 except ImportError:
33de525afa8f93e3ad7e71abd'/><select name='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
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<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
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<tr><td><span title='2022-02-04 22:31:21 +0100'>2022-02-04</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=ba60aede97330c5145f3245eb67a70b984b59116'>gnu: dunst: Fix crash on invalid pixbuf notification.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/patches/dunst-1.7.3-fix-crash.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/dunst.scm (dunst)[source]&lt;#:patches&gt;: Add it.
</span></span></td><td>Danny Milosavljevic</td></tr>
<tr><td><span title='2021-12-13 17:48:25 +0100'>2021-12-13</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=8394619baceb118df92e355377fd543bb1aa501a'>gnu: Simplify package inputs.</a><span class='msg-avail'>...<span class='msg-tooltip'>This commit was obtained by running:

  ./pre-inst-env guix style

without any additional argument.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-12-13 11:49:15 +0100'>2021-12-13</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=1052ae5f03de931b52c7a638c8e4f8d8d7093af3'>Merge branch 'master' into core-updates-frozen</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-12-12 10:24:52 +0100'>2021-12-12</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=8778ff2aec128a4d2f94b6ca383c11bda69ef077'>gnu: dunst : Update to 1.7.3.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dunst.scm (dunst): Update to 1.7.3.

Signed-off-by: Guillaume Le Vaillant &lt;glv@posteo.net&gt;
</span></span></td><td>gyara</td></tr>
<tr><td><span title='2021-11-17 23:43:14 +0100'>2021-11-17</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=3a317f7476f8c6012e166ff9f340f861938721c9'>Merge branch 'master' into core-updates-frozen</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-11-11 12:18:20 -0500'>2021-11-11</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=feab09f72abc6d6eec16a1b8d27c231c747c0e00'>gnu: gtk: Replace gdk-pixbuf+svg by librsvg.</a><span class='msg-avail'>...<span class='msg-tooltip'>With the addition of a profile hook for computing the gdk-pixbuf loaders cache
file, there is no longer a need for gdk-pixbuf+svg, and librsvg can propagate
gdk-pixbuf without fear, so replace the former for the latter.

The replacement was automated with the following command:

   $ git grep -l ',gdk-pixbuf+svg)' \
     | xargs sed 's/(".*" ,gdk-pixbuf+svg)/("librsvg" ,librsvg)/' -i

* gnu/packages/gtk.scm (gdk-pixbuf+svg): Delete package.
(gtk+-2)[propagated-inputs]: Replace gdk-pixbuf+svg with librsvg.
(gtk+)[propagated-inputs]: Likewise.
* gnu/packages/gnome.scm (gdk-pixbuf+svg): Add deprecated package.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2021-11-09 17:38:54 +0100'>2021-11-09</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=9e48ac29eb66ebbd1191528553ab0fbcb7bb9c6e'>gnu: dunst: Update to 1.7.1.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dunst.scm (dunst): Update to 1.7.1.
</span></span></td><td>Guillaume Le Vaillant</td></tr>
<tr><td><span title='2021-11-01 11:35:06 +0200'>2021-11-01</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=e1370ea8fa41417bedb437b2fc3a066b19f82c52'>gnu: dunst: Update to 1.7.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dunst.scm (dunst): Update to 1.7.0.
[source]: Fix indentation.

Signed-off-by: Efraim Flashner &lt;efraim@flashner.co.il&gt;
</span></span></td><td>Alexandr Vityazev</td></tr>