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/Python/importdl.h

@@ -5,7 +5,6 @@
 extern "C" {
 #endif
 
-
 extern const char *_PyImport_DynLoadFiletab[];
 
 extern PyObject *_PyImport_LoadDynamicModuleWithSpec(PyObject *spec, FILE *);
@@ -13,13 +12,7 @@ extern PyObject *_PyImport_LoadDynamicModuleWithSpec(PyObject *spec, FILE *);
 /* Max length of module suffix searched for -- accommodates "module.slb" */
 #define MAXSUFFIXSIZE 12
 
-#ifdef MS_WINDOWS
-#include <windows.h>
-typedef FARPROC dl_funcptr;
-#else
 typedef void (*dl_funcptr)(void);
-#endif
-
 
 #ifdef __cplusplus
 }