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/describeflags.c

@@ -0,0 +1,60 @@
+/*-*- 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 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/intrin/describeflags.internal.h"
+#include "libc/intrin/kprintf.h"
+
+// TODO(jart): Fork this function into ASAN and non-ASAN versions.
+const char *DescribeFlags(char *p, size_t n, struct DescribeFlags *d, size_t m,
+                          const char *prefix, unsigned x) {
+  bool t;
+  char b[21];
+  size_t i, j, k;
+  for (t = i = j = 0; j < m; ++j) {
+    if (d[j].flag && d[j].flag != -1 && (x & d[j].flag) == d[j].flag) {
+      x &= ~d[j].flag;
+      if (t) {
+        if (i + 1 < n) p[i++] = '|';
+      } else {
+        t = true;
+      }
+      for (k = 0; prefix && prefix[k]; ++k) {
+        if (i + 1 < n) p[i++] = prefix[k];
+      }
+      for (k = 0; d[j].name[k]; ++k) {
+        if (i + 1 < n) p[i++] = d[j].name[k];
+      }
+    }
+  }
+  if (x || !t) {
+    if (t && i + 1 < n) p[i++] = '|';
+    if (i + 1 < n) p[i++] = '0';
+    if (x) {
+      if (i + 1 < n) p[i++] = 'x';
+      k = 0;
+      do {
+        if (i + 1 < n) b[k++] = "0123456789abcdef"[x % 16];
+      } while ((x /= 16));
+      while (k--) {
+        if (i + 1 < n) p[i++] = b[k];
+      }
+    }
+  }
+  if (i < n) p[i] = 0;
+  return p;
+}