Perform build and magnum tuning

Building o//third_party/python now takes 5 seconds on my PC

This change works towards modifying Python to use runtime dispatching
when appropriate. For example, when loading the magnums in the socket
module, it's a good idea to check if the magnum is zero, because that
means the local system platform doesn't support it.

third_party/python/.gitattributes

@@ -1,17 +1,14 @@
-# Binary data types
+# -*- conf -*-
+*.com binary
 *.aif binary
 *.aifc binary
 *.aiff binary
 *.au binary
 *.bmp binary
-*.exe binary
-*.icns binary
 *.gif binary
-*.ico binary
 *.jpg binary
 *.pck binary
 *.png binary
-*.psd binary
 *.tar binary
 *.wav binary
 *.whl binary