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>
75fc0ff987b'>commit</a><a href='/guix/diff/gnu/packages/direct-connect.scm?id=0f763db448758c8b7b9ae91d6870f75fc0ff987b'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/direct-connect.scm'>
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<div class='path'>path: <a href='/guix/log/?id=0f763db448758c8b7b9ae91d6870f75fc0ff987b'>root</a>/<a href='/guix/log/gnu?id=0f763db448758c8b7b9ae91d6870f75fc0ff987b'>gnu</a>/<a href='/guix/log/gnu/packages?id=0f763db448758c8b7b9ae91d6870f75fc0ff987b'>packages</a>/<a href='/guix/log/gnu/packages/direct-connect.scm?id=0f763db448758c8b7b9ae91d6870f75fc0ff987b'>direct-connect.scm</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/gnu/packages/direct-connect.scm?id=0f763db448758c8b7b9ae91d6870f75fc0ff987b&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2017-11-30 18:19:31 +0530'>2017-11-30</span></td><td><a href='/guix/commit/gnu/packages/direct-connect.scm?id=2b1a5ed854d3d373b960ef922eb71c52937263c0'>gnu: linuxdcpp: Use scons-build-system.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/direct-connect.scm (linuxdcpp): Switch to scons-build-system.
</span></span></td><td>Arun Isaac</td></tr>
<tr><td><span title='2017-05-06 02:26:03 +0530'>2017-05-06</span></td><td><a href='/guix/commit/gnu/packages/direct-connect.scm?id=99c1554c9ba1fd22d7dfdeba221088a3849ee27b'>gnu: Add linuxdcpp.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/direct-connect.scm (linuxdcpp): New variable.
</span></span></td><td>Arun Isaac</td></tr>