Make fixes and improvements

- Introduce __assert_disable global
- Improve strsignal() thread safety
- Make system call tracing thread safe
- Fix SO_RCVTIMEO / SO_SNDTIMEO on Windows
- Refactor DescribeFoo() functions into one place
- Fix fork() on Windows when TLS and MAP_STACK exist
- Round upwards in setsockopt(SO_RCVTIMEO) on Windows
- Disable futexes on OpenBSD which seem extremely broken
- Implement a better kludge for monotonic time on Windows

libc/intrin/ksockoptnames.S

@@ -0,0 +1,52 @@
+/*-*- 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 2021 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/fmt/magnumstrs.internal.h"
+#include "libc/macros.internal.h"
+
+	.macro	.e e s
+	.long	\e - kSockOptnames
+	.long	1f - kSockOptnames
+	.rodata.str1.1
+1:	.string	"\s"
+	.previous
+	.endm
+
+	.section .rodata
+	.align 4
+	.underrun
+kSockOptnames:
+	.e	SO_DEBUG,"DEBUG"			# bool32
+	.e	SO_ACCEPTCONN,"ACCEPTCONN"		# bool32
+	.e	SO_BROADCAST,"BROADCAST"		# bool32
+	.e	SO_REUSEADDR,"REUSEADDR"		# bool32
+	.e	SO_REUSEPORT,"REUSEPORT"		# bool32
+	.e	SO_KEEPALIVE,"KEEPALIVE"		# bool32
+	.e	SO_DONTROUTE,"DONTROUTE"		# bool32
+	.e	SO_RCVTIMEO,"RCVTIMEO"			# timeval
+	.e	SO_SNDTIMEO,"SNDTIMEO"			# timeval
+	.e	SO_LINGER,"LINGER"			# linger
+	.e	SO_TYPE,"TYPE"				# int
+	.e	SO_SNDBUF,"SNDBUF"			# int
+	.e	SO_RCVBUF,"RCVBUF"			# int
+	.e	SO_RCVLOWAT,"RCVLOWAT"			# int
+	.e	SO_SNDLOWAT,"SNDLOWAT"			# int
+	.e	SO_ERROR,"ERROR"			# int
+	.long	MAGNUM_TERMINATOR
+	.endobj	kSockOptnames,globl,hidden
+	.overrun