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);
mized Guix</td><td class='sub right'></td></tr></table>
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<div class='path'>path: <a href='/guix/log/?id=e9bec5bd40865b377b1961ef2ee3b498a7c4752f'>root</a>/<a href='/guix/log/HACKING?id=e9bec5bd40865b377b1961ef2ee3b498a7c4752f'>HACKING</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/HACKING?id=e9bec5bd40865b377b1961ef2ee3b498a7c4752f&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-10-23 12:57:20 -0400'>2020-10-23</span></td><td><a href='/guix/commit/HACKING?id=73faee9fb25465f1b236f5f94e1052145655736f'>doc: Fix typo in HACKING.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Contributing): s/informations/information/.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2020-01-09 23:33:04 +0100'>2020-01-09</span></td><td><a href='/guix/commit/HACKING?id=2d315cd428484537e763d7f7c676dc5fff7995f6'>doc: Move "Commit Access" section from 'HACKING' to the manual.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Remove.
(Contributing): Update URL of the manual.
* doc/contributing.texi (Commit Access): New section.
(Submitting Patches): Add cross reference.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-01-09 23:33:04 +0100'>2020-01-09</span></td><td><a href='/guix/commit/HACKING?id=a7bde77d247ed0765f5378779d67b4668c5d7648'>doc: Add "Tracking Bugs and Patches" section.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/contributing.texi (Tracking Bugs and Patches): New section.
(Submitting Patches): Refer to it.
* doc/guix.texi: Update copyright line.
* HACKING (Using emacs-debbugs): Remove.
</span></span></td><td>Ludovic Courtès</td></tr>