dev-python/aiodns: use correct typing distribution

With the Gentoo startfiles for Python the typing distribution for
Python 3.6  and Python 3.7 is searched as external library and not as
part of the standard library.

Backport fix from 281112107c

Closes: https://github.com/gentoo/gentoo/pull/13324
Closes: https://bugs.gentoo.org/692720
Package-Manager: Portage-2.3.69, Repoman-2.3.16
Signed-off-by: Gerion Entrup <gerion.entrup@flump.de>
Signed-off-by: Zac Medico <zmedico@gentoo.org>

dev-python/aiodns/aiodns-2.0.0-r1.ebuild

@@ -21,6 +21,13 @@ RDEPEND=">=dev-python/pycares-3[${PYTHON_USEDEP}]"
 DEPEND="${RDEPEND}
 	dev-python/setuptools[${PYTHON_USEDEP}]"
 
+python_prepare_all() {
+	distutils-r1_python_prepare_all
+
+	#692720 apply https://github.com/saghul/aiodns/pull/73
+	sed -e 's|typing; python_version<"3.7"|typing; python_version<"3.5"|' -i setup.py || die
+}
+
 python_test() {
 	"${EPYTHON}" tests.py -v || die
 }