empty-system.py: Add a @system-emptying script for trim.sh

diff --git a/empty-system.py b/empty-system.py
new file mode 100755 (executable)
index 0000000..7cfafbc
--- /dev/null
+++ b/empty-system.py
@@ -0,0 +1,26 @@
+#!/usr/bin/python
+#
+# Previous discussion:
+# * RFC: replacing "packages"  2007-10-24
+#   http://thread.gmane.org/gmane.linux.gentoo.portage.devel/2575
+# * [RFC] Reducing the size of the system package set  2008-01-07
+#   http://thread.gmane.org/gmane.linux.gentoo.devel/54035
+# * Re: remove system set?  2012-08-15
+#   http://thread.gmane.org/gmane.linux.gentoo.devel/79186/focus=79412
+# * System packages in (R)DEPEND?  2008-10-12
+#   http://thread.gmane.org/gmane.linux.gentoo.devel/58488
+
+import portage
+from portage._sets import load_default_config
+
+eroot = portage.settings['EROOT']
+trees = portage.db[eroot]
+vartree = trees['vartree']
+settings = vartree.settings
+settings._init_dirs()
+setconfig = load_default_config(settings, trees)
+sets = setconfig.getSets()
+system = sets['system']
+with open('/etc/portage/make.profile/packages', 'w') as f:
+    for atom in system.getAtoms():
+        f.write('-*{0}\n'.format(atom))