disable use of python-3 for now

It doesn't build and we don't want it (yet?), so disable it for now
and wait until someone requests it to figure things out.

Change-Id: Ieefc44a187ced06fdaef37deabfe8da34b86986b
diff --git a/portage/make.defaults.in b/portage/make.defaults.in
index fce3aaa..6a758b2 100644
--- a/portage/make.defaults.in
+++ b/portage/make.defaults.in
@@ -3,6 +3,13 @@
 # Various GNU packages try to install this file when no one should be.
 INSTALL_MASK="charset.alias"
 
+# Currently no support for python-3 as it does not cross-compile.  If we do
+# enable it, it also means both py2.7 and py3.x get installed simultaneously
+# which is (usually) a waste of resources.  We'll wait for such a request to
+# figure out how to integrate things nicely into the build.
+PYTHON_TARGETS="-* python2_7"
+PYTHON_SINGLE_TARGET="-* python2_7"
+
 # We use Bionic for our C library.
 ELIBC="bionic"