Make improvements for Actually Portable Emacs

- Get SIGWINCH working again on the New Technology
- Correctly handle O_NOFOLLOW in open() on Windows
- Implement synthetic umask() functionality on Windows
- Do a better job managing file execute access on Windows
- Fill in `st_uid` and `st_gid` with username hash on Windows
- Munge UNICODE control pictures into control codes on Windows
- Do a better job ensuring Windows console settings are restored
- Introduce KPRINTF_LOG environment variable to log kprintf to a file

libc/calls/fdatasync-nt.c

@@ -23,6 +23,6 @@
 textwindows int sys_fdatasync_nt(int fd) {
   // TODO(jart): what should we do with worker pipes?
   if (!__isfdkind(fd, kFdFile)) return ebadf();
-  if (_check_interrupts(0, 0)) return -1;
+  if (_check_interrupts(0)) return -1;
   return FlushFileBuffers(g_fds.p[fd].handle) ? 0 : -1;
 }