python: Add support for installing Python eggs

pkgs/development/interpreters/python/hooks/egg-unpack-hook.sh

@@ -0,0 +1,17 @@
+# Setup hook to use in case an egg is fetched
+echo "Sourcing egg setup hook"
+
+eggUnpackPhase(){
+    echo "Executing eggUnpackPhase"
+    runHook preUnpack
+
+    cp "$src" "$(stripHash "$src")"
+
+#     runHook postUnpack # Calls find...?
+    echo "Finished executing eggUnpackPhase"
+}
+
+if [ -z "${dontUseEggUnpack-}" ] && [ -z "${unpackPhase-}" ]; then
+    echo "Using eggUnpackPhase"
+    unpackPhase=eggUnpackPhase
+fi