Support EAPI="4".
(Patch by Arfrever. Backported from Progress Overlay.)
--- python.eclass
+++ python.eclass
@@ -13,7 +13,7 @@
 
 inherit multilib
 
-if ! has "${EAPI:-0}" 0 1 2 3; then
+if ! has "${EAPI:-0}" 0 1 2 3 4; then
 	die "API of python.eclass in EAPI=\"${EAPI}\" not established"
 fi