Skip Thai character test when libthai is unavailable.

Taken from upstream bug tracker:
https://gitlab.gnome.org/GNOME/pango/merge_requests/161
https://gitlab.gnome.org/GNOME/pango/commit/b73284747ac937e31dc9191f84ed6e24284c88ee

diff --git a/tests/test-break.c b/tests/test-break.c
index 8549b678bba69360d07dce3af21d915412f20d51..47fa3009165e19a331aa04a0df4351ae2323933b 100644
--- a/tests/test-break.c
+++ b/tests/test-break.c
@@ -305,6 +305,12 @@ main (int argc, char *argv[])
       if (!strstr (name, "break"))
         continue;
 
+#ifndef HAVE_LIBTHAI
+      /* four.break involves Thai, so only test it when we have libthai */
+      if (strstr (name, "four.break"))
+        continue;
+#endif
+
       path = g_strdup_printf ("/break/%s", name);
       g_test_add_data_func_full (path, g_test_build_filename (G_TEST_DIST, "breaks", name, NULL),
                                  test_break, g_free);
d class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
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<div class='path'>path: <a href='/guix/log/?id=af7014a14059ded4425e8f7f147d08fb8ba2b5c7'>root</a>/<a href='/guix/log/tests?id=af7014a14059ded4425e8f7f147d08fb8ba2b5c7'>tests</a>/<a href='/guix/log/tests/guix-package.sh?id=af7014a14059ded4425e8f7f147d08fb8ba2b5c7'>guix-package.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-package.sh?id=af7014a14059ded4425e8f7f147d08fb8ba2b5c7&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-02-07 15:46:45 +0100'>2019-02-07</span></td><td><a href='/guix/commit/tests/guix-package.sh?id=487cbb0164c715e722b622fa800fa0b217fa132c'>profiles: Raise an error for unmatched patterns.</a><span class='msg-avail'>...<span class='msg-tooltip'>Previously, "guix package -r something-not-installed" would silently
complete.  Now an error is raised.

* guix/profiles.scm (&amp;unmatched-pattern-error): New condition type.
(manifest-matching-entries): Rewrite to raise an error when one of
PATTERNS is not matched.
* guix/ui.scm (call-with-error-handling): Handle 'unmatched-pattern-error?'.
* tests/guix-package.sh: Add test.
* tests/profiles.scm ("manifest-matching-entries"): Don't try to remove
unmatched pattern.
("manifest-matching-entries, no match"): New test.
("manifest-transaction-effects"): Remove 'remove' field.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-11-11 23:53:29 +0100'>2018-11-11</span></td><td><a href='/guix/commit/tests/guix-package.sh?id=652163154c06b47936a453f44ea35938789718de'>guix package: '--show' errors when asked for a non-existent package.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://bugs.gnu.org/33323&gt;.
Reported by swedebugia &lt;swedebugia@riseup.net&gt;.

* guix/scripts/package.scm (process-query): Call 'leave' when
'find-packages-by-name' returns the empty list.
* tests/guix-package.sh: Test it.
</span></span></td><td>Ludovic Courtès</td></tr>