gnu: xfce4-settings: Set the default icon theme to "gnome".

Fixes <http://bugs.gnu.org/21217>.

* gnu/packages/patches/xfce4-settings-defaults.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/xfce.scm (xfce4-settings)[source]: Add patch.

gnu-system.am

@@ -707,6 +707,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/xf86-video-trident-remove-mibstore.patch	\
   gnu/packages/patches/xf86-video-vmware-glibc-2.20.patch	\
   gnu/packages/patches/xfce4-panel-plugins.patch		\
+  gnu/packages/patches/xfce4-settings-defaults.patch		\
   gnu/packages/patches/xmodmap-asprintf.patch 			\
   gnu/packages/patches/zathura-plugindir-environment-variable.patch
 

gnu/packages/patches/xfce4-settings-defaults.patch

@@ -0,0 +1,29 @@
+This patch make Xfce use "gnome" as the default icon theme and enable font antialias.
+
+Taken from ArchLinux.
+
+diff -upr xfce4-settings-4.12.0.orig/xfsettingsd/xsettings.xml xfce4-settings-4.12.0/xfsettingsd/xsettings.xml
+--- xfce4-settings-4.12.0.orig/xfsettingsd/xsettings.xml	2015-02-24 03:33:11.000000000 +0200
++++ xfce4-settings-4.12.0/xfsettingsd/xsettings.xml	2015-03-01 09:52:24.376869688 +0200
+@@ -6,8 +6,8 @@
+ <?xml version="1.0" encoding="UTF-8"?>
+ <channel name="xsettings" version="1.0">
+   <property name="Net" type="empty">
+     <property name="ThemeName" type="empty"/>
+-    <property name="IconThemeName" type="empty"/>
++    <property name="IconThemeName" type="string" value="gnome"/>
+     <property name="DoubleClickTime" type="int" value="400"/>
+     <property name="DoubleClickDistance" type="int" value="5"/>
+     <property name="DndDragThreshold" type="int" value="8"/>
+@@ -19,9 +19,9 @@
+   </property>
+   <property name="Xft" type="empty">
+     <property name="DPI" type="empty"/>
+-    <property name="Antialias" type="int" value="-1"/>
++    <property name="Antialias" type="int" value="1"/>
+     <property name="Hinting" type="int" value="-1"/>
+-    <property name="HintStyle" type="string" value="hintnone"/>
++    <property name="HintStyle" type="string" value="hintfull"/>
+     <property name="RGBA" type="string" value="none"/>
+     <!-- <property name="Lcdfilter" type="string" value="none"/> -->
+   </property>

gnu/packages/xfce.scm

@@ -452,7 +452,9 @@ allows you to shutdown the computer from Xfce.")
                                   "/src/" name "-" version ".tar.bz2"))
               (sha256
                (base32
-                "108za1cmjslwzkdl76x9kwxkq8z734kg9nz8rxk057f10pqwxgh4"))))
+                "108za1cmjslwzkdl76x9kwxkq8z734kg9nz8rxk057f10pqwxgh4"))
+              (patches
+               (list (search-patch "xfce4-settings-defaults.patch")))))
     (build-system gnu-build-system)
     (native-inputs
      `(("pkg-config" ,pkg-config)