Fixes 'multiple definition errors' when building with GCC 10+

From: https://bugs.gentoo.org/710796
Originally from: https://gitlab.freedesktop.org/pipewire/pipewire/-/commit/a62e41e
and https://gitlab.freedesktop.org/pipewire/pipewire/-/commit/7a976c7

--- a/spa/plugins/bluez5/a2dp-codecs.h
+++ b/spa/plugins/bluez5/a2dp-codecs.h
@@ -284,15 +284,15 @@
         }
 }
 
-const a2dp_sbc_t bluez_a2dp_sbc;
+extern const a2dp_sbc_t bluez_a2dp_sbc;
 #if ENABLE_MP3
-const a2dp_mpeg_t bluez_a2dp_mpeg;
+extern const a2dp_mpeg_t bluez_a2dp_mpeg;
 #endif
 #if ENABLE_AAC
-const a2dp_aac_t bluez_a2dp_aac;
+extern const a2dp_aac_t bluez_a2dp_aac;
 #endif
 #if ENABLE_APTX
-const a2dp_aptx_t bluez_a2dp_aptx;
+extern const a2dp_aptx_t bluez_a2dp_aptx;
 #endif
 
 #endif
--- a/spa/plugins/bluez5/bluez5-monitor.c
+++ b/spa/plugins/bluez5/bluez5-monitor.c
@@ -75,7 +75,7 @@
 	struct spa_list transport_list;
 };
 
-struct spa_handle_factory spa_a2dp_sink_factory;
+extern struct spa_handle_factory spa_a2dp_sink_factory;
 
 static void fill_item(struct spa_bt_monitor *this, struct spa_bt_transport *transport,
 		struct spa_pod **result, struct spa_pod_builder *builder)
--- a/spa/plugins/bluez5/meson.build
+++ b/spa/plugins/bluez5/meson.build
@@ -1,7 +1,8 @@
 
 bluez5_sources = ['plugin.c',
 		  'a2dp-sink.c',
-                  'bluez5-monitor.c']
+		  'a2dp-codecs.c',
+		  'bluez5-monitor.c']
 
 bluez5lib = shared_library('spa-bluez5',
 	bluez5_sources,
9c488c0da15b4a7a8176d616ec92f8'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/guix-graph.sh'>
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<div class='path'>path: <a href='/guix/log/?id=5a6b1a55869c488c0da15b4a7a8176d616ec92f8'>root</a>/<a href='/guix/log/tests?id=5a6b1a55869c488c0da15b4a7a8176d616ec92f8'>tests</a>/<a href='/guix/log/tests/guix-graph.sh?id=5a6b1a55869c488c0da15b4a7a8176d616ec92f8'>guix-graph.sh</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/guix-graph.sh?id=5a6b1a55869c488c0da15b4a7a8176d616ec92f8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-09-26 17:36:57 +0200'>2023-09-26</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=7f3ebd6dbcae830e60b78d6bab8f1dbad90ba3a8'>tests: Adjust ‘guix graph --path’ test to latest Emacs changes.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to 3349a50d700a2112a31ac4ce6cc6639d3b4cf1e2.

* tests/guix-graph.sh: Adjust ‘path’.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-04-28 19:50:39 +0200'>2023-04-28</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=ee88acc6e22595bbf4a6f07332ed4308d6a6e3cf'>tests: guix-graph.sh: Fix expected path from emacs to libffi.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/guix-graph.sh: Change the expected path from emacs to libffi.  `guix
graph --path` outputs only one possible path, and the one it outputs for this
case has changed.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Josselin Poiret</td></tr>
<tr><td><span title='2023-04-21 16:16:38 +0200'>2023-04-21</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=37dd69b44511dc73eb04bdebe8d82c9a0386338e'>tests: Fix checks for expected failures.</a><span class='msg-avail'>...<span class='msg-tooltip'>Addresses &lt;https://issues.guix.gnu.org/62406&gt;.

With 'set -e', a return status inverted with '!' does not cause the shell to
exit immediately.  Instead use '&amp;&amp; false' to indicate an expected failure.

* tests/guix-archive.sh, tests/guix-build-branch.sh, tests/guix-build.sh,
tests/guix-daemon.sh, tests/guix-download.sh,
tests/guix-environment-container.sh, tests/guix-environment.sh,
tests/guix-gc.sh, tests/guix-git-authenticate.sh, tests/guix-graph.sh,
tests/guix-hash.sh, tests/guix-home.sh, tests/guix-pack-relocatable.sh,
tests/guix-pack.sh, tests/guix-package-aliases.sh, tests/guix-package-net.sh,
tests/guix-package.sh, tests/guix-refresh.sh, tests/guix-shell.sh,
tests/guix-style.sh, tests/guix-system.sh: Replace uses of '! ...' with
'... &amp;&amp; false' or `test ! ...` as appropriate.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2022-01-16 23:56:56 +0100'>2022-01-16</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=a1037aa87b39d4c774fe398fc97a58bafeb063d1'>tests: Clean up after 'tests/guix-graph.sh'.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes a regression introduced in
a773c3142dd168e1c4480614d3f5fd9d003954cd, which would lead the first
'trap' to be ignored, thereby leaving 't-guix-graph-*' directories
behind it.

* tests/guix-graph.sh: Remove first 'trap' line that had no effect;
replace second 'trap' line.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-09-28 21:06:36 -0500'>2020-09-28</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=d8934360d2453a403b5433e71d09188e4ed23b57'>tests: Simplify shell exit status negation;</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/guix-archive.sh, tests/guix-build-branch.sh, tests/guix-build.sh,
tests/guix-daemon.sh, tests/guix-download.sh, tests/guix-environment.sh,
tests/guix-gc.sh, tests/guix-git-authenticate.sh, tests/guix-graph.sh,
tests/guix-hash.sh, tests/guix-lint.sh, tests/guix-pack-relocatable.sh,
tests/guix-pack.sh, tests/guix-package-aliases.sh, tests/guix-package-net.sh,
tests/guix-package.sh: Use the shell '!' keyword to negate command exit status
in place of 'if ...; then false; else true; fi'
</span></span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2020-05-11 23:30:55 +0200'>2020-05-11</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=88a96c568c47c97d05d883ada5afbc4e1200b10f'>guix graph: Add '--path'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/graph.scm (display-path): New procedure.
(%options, show-help): Add '--path'.
(guix-graph): Handle it.
* tests/guix-graph.sh: Add tests.
* doc/guix.texi (Invoking guix graph): Document it.
(Invoking guix size): Mention it.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-01-16 15:27:20 +0100'>2020-01-16</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=ee9a735bc8f544cf8eedc6c6a7e4ed2962663013'>graph: Add '--load-path' option.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/graph.scm (%option): Add '--load-path' option.
* doc/guix.texi: Document it.
* tests/guix-graph.sh: Test it.
</span></span></td><td>Pierre Neidhardt</td></tr>
<tr><td><span title='2019-11-07 18:39:55 +0100'>2019-11-07</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=3e962e59d849e4300e447d94487684102d9d412e'>graph: Support package transformation options.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/scripts/graph.scm (%options): Append %TRANSFORMATION-OPTIONS.
(show-help): Call 'show-transformation-options-help'.
(guix-graph): Call 'options-&gt;transformation' and use it.
* tests/guix-graph.sh: Add test.
* doc/guix.texi (Invoking guix graph): Document it.
</span></span></td><td>Ludovic Courtès</td></tr>