Keywords for ia64 keep being requested for dev-python/greenlet.
Explicit mask should be a good place to add more context on why
it's not easy to keyword.
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
--- /dev/null
+# Copyright 2019-2020 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+# Sergei Trofimovich <slyfox@gentoo.org> (2020-05-02)
+# greenlet needs arch-specific stack switching code. There is no ia64 port.
+dev-python/greenlet
+virtual/python-greenlet