profiles: Prepare for Python 3.9

Signed-off-by: Michał Górny <mgorny@gentoo.org>

profiles/base/package.use.force

@@ -127,6 +127,7 @@ dev-lang/python-exec python_targets_python2_7
 dev-lang/python-exec python_targets_python3_6
 dev-lang/python-exec python_targets_python3_7
 dev-lang/python-exec python_targets_python3_8
+dev-lang/python-exec python_targets_python3_9
 dev-lang/python-exec python_targets_pypy3
 
 # Zac Medico <zmedico@gentoo.org> (2010-10-20)

profiles/base/use.stable.mask

@@ -1,9 +1,14 @@
-# Copyright 1999-2019 Gentoo Authors
+# Copyright 1999-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 # This file requires eapi 5 or later. New entries go on top.
 # Please use the same syntax as in use.mask
 
+# Michał Górny <mgorny@gentoo.org> (2020-05-25)
+# Python 3.9 is not yet stable.
+python_targets_python3_9
+python_single_target_python3_9
+
 # Sergei Trofimovich <slyfox@gentoo.org> (2020-04-13)
 # dev-vcs/darcs (dev-lang/ghc) has no stable keywords.
 darcs

profiles/desc/python_single_target.desc

@@ -1,4 +1,4 @@
-# Copyright 1999-2019 Gentoo Authors.
+# Copyright 1999-2020 Gentoo Authors.
 # Distributed under the terms of the GNU General Public License v2
 
 # This file contains descriptions of PYTHON_SINGLE_TARGET USE_EXPAND flags.
@@ -7,4 +7,5 @@ python2_7 - Build for Python 2.7 only
 python3_6 - Build for Python 3.6 only
 python3_7 - Build for Python 3.7 only
 python3_8 - Build for Python 3.8 only
+python3_9 - Build for Python 3.9 only
 pypy3 - Build for PyPy3 only

profiles/desc/python_targets.desc

@@ -7,4 +7,5 @@ python2_7 - Build with Python 2.7
 python3_6 - Build with Python 3.6
 python3_7 - Build with Python 3.7
 python3_8 - Build with Python 3.8
+python3_9 - Build with Python 3.9
 pypy3 - Build with PyPy3