Elevate Windows production worthiness

- SQLite file locking now works on Windows
- SQLite will now use fdatasync() on non-Apple platforms
- Fix Ctrl-C handler on Windows to not crash with TLS
- Signals now work in multithreaded apps on Windows
- fcntl() will now accurately report EINVAL errors
- fcntl() now has excellent --strace logging
- Token bucket replenish now go 100x faster
- *NSYNC cancellations now work on Windows
- Support closefrom() on NetBSD

test/libc/thread/pthread_kill_test.c

@@ -0,0 +1,54 @@
+/*-*- 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/calls/calls.h"
+#include "libc/calls/struct/sigaction.h"
+#include "libc/errno.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/testlib/testlib.h"
+#include "libc/thread/thread.h"
+
+int fds[2];
+_Thread_local sig_atomic_t gotsig;
+
+void OnSig(int sig) {
+  gotsig = 1;
+}
+
+void *ReadWorker(void *arg) {
+  char buf[8];
+  ASSERT_SYS(EINTR, -1, read(fds[0], buf, 8));
+  ASSERT_TRUE(gotsig);
+  return 0;
+}
+
+TEST(pthread_kill, canCancelReadOperation) {
+  pthread_t t;
+  struct sigaction oldsa;
+  struct sigaction sa = {.sa_handler = OnSig};
+  ASSERT_SYS(0, 0, sigaction(SIGUSR1, &sa, &oldsa));
+  ASSERT_SYS(0, 0, pipe(fds));
+  ASSERT_EQ(0, pthread_create(&t, 0, ReadWorker, 0));
+  ASSERT_SYS(0, 0, usleep(100000));  // potentially flaky
+  ASSERT_EQ(0, pthread_kill(t, SIGUSR1));
+  ASSERT_EQ(0, pthread_join(t, 0));
+  ASSERT_FALSE(gotsig);
+  ASSERT_SYS(0, 0, close(fds[0]));
+  ASSERT_SYS(0, 0, close(fds[1]));
+  ASSERT_SYS(0, 0, sigaction(SIGUSR1, &oldsa, 0));
+}