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

libc/nexgen32e/explicit_bzero.S

@@ -1,49 +0,0 @@
-/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
-│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/macros.internal.h"
-
-//	Sets memory to zero w/ accompanying non-optimizing macro.
-//
-//	This is intended for security-conscious applications. This
-//	implementation also hoses every register the abi allows. A
-//	concomitant prototype (str.h) countermands compiler magic.
-//
-//	@param	rdi is dest
-//	@param	rsi is the number of bytes to set
-explicit_bzero:
-	.leafprologue
-	mov	%rsi,%rcx
-	xor	%eax,%eax
-	rep stosb
-	xor	%edx,%edx
-	xor	%edi,%edi
-	xor	%esi,%esi
-	xor	%r8,%r8
-	xor	%r9,%r9
-	xor	%r10,%r10
-	xor	%r11,%r11
-	pxor	%xmm0,%xmm0
-	pxor	%xmm1,%xmm1
-	pxor	%xmm2,%xmm2
-	pxor	%xmm3,%xmm3
-	pxor	%xmm4,%xmm4
-	pxor	%xmm5,%xmm5
-	.leafepilogue
-	.endfn	explicit_bzero,globl
-	.source	__FILE__

libc/nexgen32e/imapxlatab.S

@@ -18,7 +18,6 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/macros.internal.h"
 .text.startup
-.align	8
 
 //	Identity maps 256-byte translation table.
 //

libc/nexgen32e/ktolower.S

@@ -18,23 +18,17 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/macros.internal.h"
 
+	.initbss 300,_init_kToLower
 //	ASCII uppercase → lowercase translation tables.
 //
 //		char kToLower[256];
-//		char16_t kToLower16[256];
 //
-//	@note	kToLower16 saves 128kb; CMOVcc can't even 8-bit
-	.initbss 300,_init_kToLower
+//	@see	kToUpper
 kToLower:
 	.rept	256
 	.byte	0
 	.endr
 	.endobj	kToLower,globl,hidden
-kToLower16:
-	.rept	256
-	.short	0
-	.endr
-	.endobj	kToLower16,globl,hidden
 	.previous
 
 	.init.start 300,_init_kToLower
@@ -44,17 +38,11 @@ kToLower16:
 	xor	%ecx,%ecx
 0:	inc	%ecx
 	addb	$0x20,'A'-1(%rsi,%rcx)
-	cmp	$'Z'-'A',%ecx
+	cmp	$'Z'-'A'+1,%ecx
 	jne	0b
-	xor	%eax,%eax
-	mov	$256,%ecx
-0:	lodsb
-	stosw
-	.loop	0b
 	pop	%rsi
 	.init.end 300,_init_kToLower
 
 	.type	gperf_downcase,@object
 	.globl	gperf_downcase
 	gperf_downcase = kToLower
-	.source	__FILE__

libc/nexgen32e/ktoupper.S

@@ -1,5 +1,5 @@
 /*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
-│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
+│vi: set et ft=asm ts=8 sw=8 fenc=utf-8                                     :vi│
 ╞══════════════════════════════════════════════════════════════════════════════╡
 │ Copyright 2020 Justine Alexandra Roberts Tunney                              │
 │                                                                              │
@@ -18,17 +18,27 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/macros.internal.h"
 
-//	Sets memory to zero.
+	.initbss 300,_init_kToUpper
+//	ASCII lowercase → uppercase translation tables.
 //
-//	C code should always favor memset(), since that's the one we've
-//	prototyped with the best optimizations. This definition is used
-//	by old code and sometimes code generators, as a thunk.
+//		char kToUpper[256];
 //
-//	@param	rdi is dest
-//	@param	rsi is the number of bytes to set
-//	@see	memset(), explicit_bzero()
-bzero:	mov	%rsi,%rdx
-	xor	%esi,%esi
-	jmp	MemSet
-	.endfn	bzero,globl
-	.source	__FILE__
+//	@see	kToLower
+kToUpper:
+	.rept	256
+	.byte	0
+	.endr
+	.endobj	kToUpper,globl,hidden
+	.previous
+
+	.init.start 300,_init_kToUpper
+	push	%rdi
+	call	imapxlatab
+	xchg	%rsi,(%rsp)
+	xor	%ecx,%ecx
+0:	inc	%ecx
+	subb	$0x20,'a'-1(%rsi,%rcx)
+	cmp	$'z'-'a'+1,%ecx
+	jne	0b
+	pop	%rsi
+	.init.end 300,_init_kToUpper