Undiamond Python headers

This change gets the Python codebase into a state where it conforms to
the conventions of this codebase. It's now possible to include headers
from Python, without worrying about ordering. Python has traditionally
solved that problem by "diamonding" everything in Python.h, but that's
problematic since it means any change to any Python header invalidates
all the build artifacts. Lastly it makes tooling not work. Since it is
hard to explain to Emacs when I press C-c C-h to add an import line it
shouldn't add the header that actually defines the symbol, and instead
do follow the nonstandard Python convention.

Progress has been made on letting Python load source code from the zip
executable structure via the standard C library APIs. System calss now
recognizes zip!FILENAME alternative URIs as equivalent to zip:FILENAME
since Python uses colon as its delimiter.

Some progress has been made on embedding the notice license terms into
the Python object code. This is easier said than done since Python has
an extremely complicated ownership story.

- Some termios APIs have been added
- Implement rewinddir() dirstream API
- GetCpuCount() API added to Cosmopolitan Libc
- More bugs in Cosmopolitan Libc have been fixed
- zipobj.com now has flags for mangling the path
- Fixed bug a priori with sendfile() on certain BSDs
- Polyfill F_DUPFD and F_DUPFD_CLOEXEC across platforms
- FIOCLEX / FIONCLEX now polyfilled for fast O_CLOEXEC changes
- APE now supports a hybrid solution to no-self-modify for builds
- Many BSD-only magnums added, e.g. O_SEARCH, O_SHLOCK, SF_NODISKIO

third_party/python/Include/pyarena.h

@@ -1,6 +1,7 @@
 #ifndef Py_LIMITED_API
 #ifndef Py_PYARENA_H
 #define Py_PYARENA_H
+#include "third_party/python/Include/object.h"
 COSMOPOLITAN_C_START_
 /* clang-format off */
 
@@ -28,8 +29,8 @@ typedef struct _arena PyArena;
    XXX block_new(DEFAULT_BLOCK_SIZE) returns NULL, that's passed on but
    XXX an exception is not set in that case).
 */
-PyAPI_FUNC(PyArena *) PyArena_New(void);
-PyAPI_FUNC(void) PyArena_Free(PyArena *);
+PyArena * PyArena_New(void);
+void PyArena_Free(PyArena *);
 
 /* Mostly like malloc(), return the address of a block of memory spanning
  * `size` bytes, or return NULL (without setting an exception) if enough
@@ -43,13 +44,13 @@ PyAPI_FUNC(void) PyArena_Free(PyArena *);
  * until PyArena_Free(ar) is called, at which point all pointers obtained
  * from the arena `ar` become invalid simultaneously.
  */
-PyAPI_FUNC(void *) PyArena_Malloc(PyArena *, size_t size);
+void * PyArena_Malloc(PyArena *, size_t size);
 
 /* This routine isn't a proper arena allocation routine.  It takes
  * a PyObject* and records it so that it can be DECREFed when the
  * arena is freed.
  */
-PyAPI_FUNC(int) PyArena_AddPyObject(PyArena *, PyObject *);
+int PyArena_AddPyObject(PyArena *, PyObject *);
 
 COSMOPOLITAN_C_END_
 #endif /* !Py_PYARENA_H */