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/Lib/hashlib.py

@@ -11,7 +11,7 @@ new(name, data=b'', **kwargs) - returns a new hash object implementing the
 Named constructor functions are also available, these are faster
 than using new(name):
 
-md5(), sha1(), sha224(), sha256(), sha384(), sha512(), blake2b(), blake2s(),
+md5(), sha1(), sha224(), sha256(), sha384(), sha512(),
 sha3_224, sha3_256, sha3_384, sha3_512, shake_128, and shake_256.
 
 More algorithms may be available on your platform but the above are guaranteed
@@ -56,7 +56,6 @@ More condensed:
 # This tuple and __get_builtin_constructor() must be modified if a new
 # always available algorithm is added.
 __always_supported = ('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512',
-                      'blake2b', 'blake2s',
                       'sha3_224', 'sha3_256', 'sha3_384', 'sha3_512',
                       'shake_128', 'shake_256')
 
@@ -90,10 +89,6 @@ def __get_builtin_constructor(name):
             import _sha512
             cache['SHA384'] = cache['sha384'] = _sha512.sha384
             cache['SHA512'] = cache['sha512'] = _sha512.sha512
-        elif name in ('blake2b', 'blake2s'):
-            import _blake2
-            cache['blake2b'] = _blake2.blake2b
-            cache['blake2s'] = _blake2.blake2s
         elif name in {'sha3_224', 'sha3_256', 'sha3_384', 'sha3_512',
                       'shake_128', 'shake_256'}:
             import _sha3
@@ -114,9 +109,6 @@ def __get_builtin_constructor(name):
 
 
 def __get_openssl_constructor(name):
-    if name in {'blake2b', 'blake2s'}:
-        # Prefer our blake2 implementation.
-        return __get_builtin_constructor(name)
     try:
         f = getattr(_hashlib, 'openssl_' + name)
         # Allow the C module to raise ValueError.  The function will be
@@ -140,12 +132,6 @@ def __hash_new(name, data=b'', **kwargs):
     """new(name, data=b'') - Return a new hashing object using the named algorithm;
     optionally initialized with data (which must be a bytes-like object).
     """
-    if name in {'blake2b', 'blake2s'}:
-        # Prefer our blake2 implementation.
-        # OpenSSL 1.1.0 comes with a limited implementation of blake2b/s.
-        # It does neither support keyed blake2 nor advanced features like
-        # salt, personal, tree hashing or SSE.
-        return __get_builtin_constructor(name)(data, **kwargs)
     try:
         return _hashlib.new(name, data)
     except ValueError: