gnu: liblxqt: Fix build with Qt 5.5.

* gnu/packages/patches/liblxqt-include.patch: New file.
* gnu-system.am (dist_patch_DATA): Register patch.
* gnu/packages/lxqt.scm (liblxqt)[source]: Use patch.

gnu-system.am

@@ -494,6 +494,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/libcanberra-sound-theme-freedesktop.patch \
   gnu/packages/patches/libevent-dns-tests.patch			\
   gnu/packages/patches/liboop-mips64-deplibs-fix.patch		\
+  gnu/packages/patches/liblxqt-include.patch			\
   gnu/packages/patches/libmad-armv7-thumb-pt1.patch		\
   gnu/packages/patches/libmad-armv7-thumb-pt2.patch		\
   gnu/packages/patches/libmad-frame-length.patch		\

gnu/packages/lxqt.scm

@@ -23,6 +23,7 @@
   #:use-module (guix packages)
   #:use-module (guix utils)
   #:use-module (guix build-system cmake)
+  #:use-module (gnu packages)
   #:use-module (gnu packages kde-frameworks)
   #:use-module (gnu packages pkg-config)
   #:use-module (gnu packages qt))
@@ -67,9 +68,11 @@ in Qt.")
        (uri
          (string-append "https://github.com/lxde/" name "/archive/"
                         version ".tar.gz"))
-       (file-name (string-append name "-" version ".tar.gz"))       (sha256
+       (file-name (string-append name "-" version ".tar.gz"))
+       (sha256
         (base32
-         "0mbl3qc0yfgfsndqrw8vg8k5irsy0pg2wrad8nwv0aphphd4n7rg"))))
+         "0mbl3qc0yfgfsndqrw8vg8k5irsy0pg2wrad8nwv0aphphd4n7rg"))
+       (patches (map search-patch '("liblxqt-include.patch")))))
     (build-system cmake-build-system)
     (arguments
      `(#:tests? #f))

gnu/packages/patches/liblxqt-include.patch

@@ -0,0 +1,14 @@
+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"
+