Patch to fix build with Qt 5.5, taken from upstream:
   https://github.com/lxde/liblxqt/commit/7303ea207de0771d6f450a31ec4a1ce69202869b

diff -u -r liblxqt-0.9.0.orig/lxqtnotification.h liblxqt-0.9.0/lxqtnotification.h
--- liblxqt-0.9.0.orig/lxqtnotification.h	2015-07-27 22:49:05.365166482 +0200
+++ liblxqt-0.9.0/lxqtnotification.h	2015-07-27 22:49:36.897606619 +0200
@@ -25,6 +25,7 @@
 #ifndef LXQTNOTIFICATION_H
 #define LXQTNOTIFICATION_H
 
+#include <QObject>
 #include <QStringList>
 #include "lxqtglobals.h"
 
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<div class='path'>path: <a href='/guix/log/?id=597f324dcd4251f47b4ab892ca1ec9359d0420e8'>root</a>/<a href='/guix/log/po?id=597f324dcd4251f47b4ab892ca1ec9359d0420e8'>po</a>/<a href='/guix/log/po/doc?id=597f324dcd4251f47b4ab892ca1ec9359d0420e8'>doc</a>/<a href='/guix/log/po/doc/guix-manual.fr.po?id=597f324dcd4251f47b4ab892ca1ec9359d0420e8'>guix-manual.fr.po</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/po/doc/guix-manual.fr.po?id=597f324dcd4251f47b4ab892ca1ec9359d0420e8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-09-02 04:06:52 +0200'>2021-09-02</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=1ff2092a39dc5c7c7cd9b4a0ba4b59f92e738efc'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/packages/it.po: New file.
* po/packages/LINGUAS: Add `it'.
* po/*/*.po: Update translations.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2021-08-04 14:49:53 +0200'>2021-08-04</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=6c10c96fedf707d7be059aeb79bd5c8e2d2fa210'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/doc/guix-cookbook.ru.po: New file.
* po/doc/guix-cookbook.sk.po: New file.
* po/*/*.po: Update translations.
* doc/local.mk (COOKBOOK_LANGUAGES): Add ru and sk.
(info_TEXINFOS): Add Russian and Slovak cookbooks.
* po/doc/local.mk (DOC_COOKBOOK_PO_FILES): Add Russian and Slovak po
files.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2021-05-11 09:17:00 -0400'>2021-05-11</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=a0178d34f582b50e9bdbb0403943129ae5b560ff'>nls: Update translations.</a></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2021-05-10 22:34:43 -0400'>2021-05-10</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=21fcced608c93e1ac836cdd9ab8c5d200c667e75'>nls: Update translations.</a></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2021-04-18 13:17:35 +0200'>2021-04-18</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=5ebe6904ea3881029e41147f49981ec2bd5f6cc7'>nls: Update 'fr' translations.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2021-01-28 16:41:18 +0100'>2021-01-28</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=a00af779047d92c0c0b4817b870bcae7fd610259'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2021-01-22 08:48:00 +0100'>2021-01-22</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=02e5c95db958a434a42c83f19c7f65437776831e'>Revert "nls: Update 'fr' translation."</a><span class='msg-avail'>...<span class='msg-tooltip'>This reverts commit 5d03ef73c3c1d995714abdaff650f73ac9fafc0f, which led
to these errors:

  /gnu/store/…-guix/fr.po:7206: 'msgstr' is not a valid Scheme format string, unlike 'msgid'. Reason: In the directive number 3, the character ' ' is not a valid conversion specifier.
  /gnu/store/…-guix/fr.po:7554: format specifications in 'msgid' and 'msgstr' are not equivalent
  /gnu/store/…-gettext-minimal-0.20.1/bin/msgfmt: found 2 fatal errors
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-01-22 00:31:28 +0100'>2021-01-22</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=5d03ef73c3c1d995714abdaff650f73ac9fafc0f'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2020-12-03 16:18:45 +0100'>2020-12-03</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=41fb3d5a9aa227b078fb95fdbf21d8198916a832'>nls: Update 'fr' translation of the manual.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-11-21 15:49:36 +0100'>2020-11-21</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=cf53ea79dda20c9ea90e3ca84bf7fdfd80b52e7d'>nls: Update 'fr' translation of the manual.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-11-09 00:14:17 +0100'>2020-11-09</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=f0ad0e85cdae95df17b2f66fec97fcf0a4e70a0b'>nls: Update 'fr' translations.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2020-11-03 12:47:43 +0100'>2020-11-03</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=595cd9cdb9070ffc6bb8e7b5c7d1285dcb756f8b'>nls: Update translations of the manual.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2020-10-30 00:59:37 +0100'>2020-10-30</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=61e839a9f9f7cc91982af696775c4f4ac72525f0'>nls: Update 'fr' translation of the manual.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2020-10-16 15:00:49 +0200'>2020-10-16</span></td><td><a href='/guix/commit/po/doc/guix-manual.fr.po?id=4dd989708c7ab34df0b60ce9b6c0a8ca5c15e858'>nls: Update manual translations.</a></td><td>Ludovic Courtès</td></tr>