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

third_party/musl/lockf.c

@@ -30,6 +30,8 @@
 #include "libc/calls/weirdtypes.h"
 #include "libc/errno.h"
 #include "libc/sysv/consts/f.h"
+#include "libc/sysv/errfuns.h"
+#include "third_party/musl/lockf.h"
 
 asm(".ident\t\"\\n\\n\
 Musl libc (MIT License)\\n\
@@ -44,25 +46,20 @@ int lockf(int fd, int op, off_t size)
 		.l_whence = SEEK_CUR,
 		.l_len = size,
 	};
-	if (op == F_TEST){
+	switch (op) {
+	case F_TEST:
 		l.l_type = F_RDLCK;
 		if (fcntl(fd, F_GETLK, &l) < 0)
 			return -1;
 		if (l.l_type == F_UNLCK || l.l_pid == getpid())
 			return 0;
-		errno = EACCES;
-		return -1;
-	}
-	if (op == F_ULOCK) {
+		return eacces();
+	case F_ULOCK:
 		l.l_type = F_UNLCK;
+	case F_TLOCK:
 		return fcntl(fd, F_SETLK, &l);
-	}
-	if (op == F_TLOCK) {
-		return fcntl(fd, F_SETLK, &l);
-	}
-	if (op == F_LOCK) {
+	case F_LOCK:
 		return fcntl(fd, F_SETLKW, &l);
 	}
-	errno = EINVAL;
-	return -1;
+	return einval();
 }