Make improvements

This change progresses our AARCH64 support:

- The AARCH64 build and tests are now passing
- Add 128-bit floating-point support to printf()
- Fix clone() so it initializes cosmo's x28 TLS register
- Fix TLS memory layout issue with aarch64 _Alignas vars
- Revamp microbenchmarking tools so they work on aarch64
- Make some subtle improvements to aarch64 crash reporting
- Make kisdangerous() memory checks more accurate on aarch64
- Remove sys_open() since it's not available on Linux AARCH64

This change makes general improvements to Cosmo and Redbean:

- Introduce GetHostIsa() function in Redbean
- You can now feature check using pledge(0, 0)
- You can now feature check using unveil("",0)
- Refactor some more x86-specific asm comments
- Refactor and write docs for some libm functions
- Make the mmap() API behave more similar to Linux
- Fix WIFSIGNALED() which wrongly returned true for zero
- Rename some obscure cosmo keywords from noFOO to dontFOO

libc/tinymath/lrintl.c

@@ -1,68 +1,41 @@
-/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8   -*-│
-│vi: set et ft=c ts=8 tw=8 fenc=utf-8                                       :vi│
-╚──────────────────────────────────────────────────────────────────────────────╝
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
 │                                                                              │
-│  Musl Libc                                                                   │
-│  Copyright © 2005-2014 Rich Felker, et al.                                   │
-│                                                                              │
-│  Permission is hereby granted, free of charge, to any person obtaining       │
-│  a copy of this software and associated documentation files (the             │
-│  "Software"), to deal in the Software without restriction, including         │
-│  without limitation the rights to use, copy, modify, merge, publish,         │
-│  distribute, sublicense, and/or sell copies of the Software, and to          │
-│  permit persons to whom the Software is furnished to do so, subject to       │
-│  the following conditions:                                                   │
-│                                                                              │
-│  The above copyright notice and this permission notice shall be              │
-│  included in all copies or substantial portions of the Software.             │
-│                                                                              │
-│  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,             │
-│  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF          │
-│  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.      │
-│  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY        │
-│  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,        │
-│  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE           │
-│  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                      │
+│ 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/limits.h"
 #include "libc/math.h"
 #include "libc/runtime/fenv.h"
-#include "libc/tinymath/expo.internal.h"
-#include "libc/tinymath/feval.internal.h"
 #if !(LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024)
 
-asm(".ident\t\"\\n\\n\
-Musl libc (MIT License)\\n\
-Copyright 2005-2014 Rich Felker, et. al.\"");
-asm(".include \"libc/disclaimer.inc\"");
-// clang-format off
-
 /**
- * Rounds to nearest integer.
+ * Rounds to integer in current rounding mode.
+ *
+ * The floating-point exception `FE_INEXACT` is raised if the result is
+ * different from the input.
  */
-long lrintl(long double x)
-{
-#ifdef FE_INEXACT
-/*
-see comments in lrint.c
-
-Note that if LONG_MAX == 0x7fffffffffffffff && LDBL_MANT_DIG == 64
-then x == 2**63 - 0.5 is the only input that overflows and
-raises inexact (with tonearest or upward rounding mode)
-*/
-// #pragma STDC FENV_ACCESS ON
-	int e;
-
-	e = fetestexcept(FE_INEXACT);
-	x = rintl(x);
-	if (!e && (x > LONG_MAX || x < LONG_MIN))
-		feclearexcept(FE_INEXACT);
-	/* conversion */
-	return x;
-#else
-	return rintl(x);
-#endif
+long lrintl(long double x) {
+  fenv_t env;
+  long double y;
+  feholdexcept(&env);
+  y = rintl(x);
+  if (fetestexcept(FE_INVALID)) {
+    feclearexcept(FE_INEXACT);
+  }
+  feupdateenv(&env);
+  return y;
 }
 
 #endif /* long double is long */