Make some systemic improvements

- add vdso dump utility
- tests now log stack usage
- rename g_ftrace to __ftrace
- make internal spinlocks go faster
- add conformant c11 atomics library
- function tracing now logs stack usage
- make function call tracing thread safe
- add -X unsecure (no ssl) mode to redbean
- munmap() has more consistent behavior now
- pacify fsync() calls on python unit tests
- make --strace flag work better in redbean
- start minimizing and documenting compiler flags

libc/intrin/sched_yield.S

@@ -0,0 +1,54 @@
+/*-*- 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 2022 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/dce.h"
+#include "libc/sysv/consts/nr.h"
+#include "libc/macros.internal.h"
+
+//	Asks kernel to let other threads be scheduled.
+//
+//	@return	0 on success, or -1 w/ errno
+sched_yield:
+	push	%rbp
+	mov	%rsp,%rbp
+	testb	IsWindows()
+	jnz	1f
+
+//	UNIX Support
+	mov	__NR_sched_yield,%eax
+	syscall
+	jmp	2f
+
+//	Windows Support
+//
+//	A value of zero, together with the bAlertable parameter set to
+//	FALSE, causes the thread to relinquish the remainder of its time
+//	slice to any other thread that is ready to run, if there are no
+//	pending user APCs on the calling thread. If there are no other
+//	threads ready to run and no user APCs are queued, the function
+//	returns immediately, and the thread continues execution.
+//	                                  ──Quoth MSDN
+1:	xor	%ecx,%ecx
+	xor	%edx,%edx
+	ntcall	__imp_SleepEx
+	xor	%eax,%eax
+
+2:	pop	%rbp
+	ret
+	.endfn	sched_yield,globl
+	.previous