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/Objects/floatobject.c

@@ -1,15 +1,12 @@
+/* clang-format off */
 /* Float object implementation */
 
 /* XXX There should be overflow checks here, but it's hard to check
    for any kind of float exception without losing portability. */
 
-#include "Python.h"
+#include "third_party/python/Include/Python.h"
 #include "libc/runtime/fenv.h"
 
-#include <ctype.h>
-#include <float.h>
-
-
 /* Special free list
    free_list is a singly-linked list of available PyFloatObjects, linked
    via abuse of their ob_type members.