Added qtxdg build dependencies

That will make the packaging more readable and understandable

debian/changelog

@@ -1,3 +1,12 @@
+liblxqt (0.12.0-2) experimental; urgency=medium
+
+  * Re-added explicit build dependencies, make the packaging more 
+    understandable:
+    - libqt5xdg-dev (>= 3.1.0)
+    - libqt5xdgiconloader-dev (>= 3.1.0)
+
+ -- Alf Gaida <agaida@siduction.org>  Sun, 22 Oct 2017 17:28:18 +0200
+
 liblxqt (0.12.0-1) experimental; urgency=medium
 
   * Cherry-picking upstream version 0.12.0.

debian/control

@@ -9,6 +9,8 @@ Build-Depends: debhelper (>= 10),
                libqt5svg5-dev,
                libkf5windowsystem-dev,
                libqt5x11extras5-dev,
+               libqt5xdg-dev (>= 3.1.0),
+               libqt5xdgiconloader-dev (>= 3.1.0),
                libx11-dev,
                libxss-dev,
                lxqt-build-tools (>= 0.4.0)