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>
commit</a><a href='/guix/diff/gnu/artwork.scm?id=30544dabfd536d710b6b22696ce475415f33554c'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/artwork.scm'>
<input type='hidden' name='id' value='30544dabfd536d710b6b22696ce475415f33554c'/><input type='hidden' name='showmsg' value='1'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=30544dabfd536d710b6b22696ce475415f33554c&amp;showmsg=1'>root</a>/<a href='/guix/log/gnu?id=30544dabfd536d710b6b22696ce475415f33554c&amp;showmsg=1'>gnu</a>/<a href='/guix/log/gnu/artwork.scm?id=30544dabfd536d710b6b22696ce475415f33554c&amp;showmsg=1'>artwork.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/artwork.scm?id=30544dabfd536d710b6b22696ce475415f33554c'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2019-06-10 23:11:07 +0200'>2019-06-10</span></td><td class='logsubject'><a href='/guix/commit/gnu/artwork.scm?id=226a3605d6cabeb71247a732a99d625c9cfafa74'>artwork: Update snapshot to 2f2fe74.</a></td><td>Diego Nicola Barbato</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/artwork.scm (%artwork-repository): Update to 2f2fe74.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;


</td></tr>
<tr class='logheader'><td><span title='2019-03-05 23:08:53 +0100'>2019-03-05</span></td><td class='logsubject'><a href='/guix/commit/gnu/artwork.scm?id=5387971a9ecf511e1dbbac992af3808437e58d56'>artwork: Update snapshot to b975164.</a></td><td>Ludovic Courtès</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/artwork.scm (%artwork-repository): Update to b975164.


</td></tr>
<tr class='logheader'><td><span title='2019-02-10 23:25:01 +0100'>2019-02-10</span></td><td class='logsubject'><a href='/guix/commit/gnu/artwork.scm?id=5e6a5aeebd7b735e5d5f2eed496cc1c7e8a5b4c9'>artwork: Update snapshot to e951905.</a></td><td>Ludovic Courtès</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/artwork.scm (%artwork-repository): Update to e951905.


</td></tr>
<tr class='logheader'><td><span title='2018-11-05 00:08:47 +0100'>2018-11-05</span></td><td class='logsubject'><a href='/guix/commit/gnu/artwork.scm?id=688d1a01e45eb1277a6337987bfd53f3fe3caaec'>artwork: Clone over HTTPS.</a></td><td>Ludovic Courtès</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
Suggested by Leo Famulari &lt;leo@famulari.name&gt;
at &lt;https://lists.gnu.org/archive/html/help-guix/2018-11/msg00039.html&gt;.

* gnu/artwork.scm (%artwork-repository): Switch to HTTPS URL.


</td></tr>