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

test/libc/calls/reservefd_test.c

@@ -50,6 +50,10 @@ __static_yoink("libc/testlib/hyperion.txt");
 #define THREADS 8
 
 void SetUpOnce(void) {
+  for (int i = 3; i < 200; ++i) {
+    close(i);
+  }
+  errno = 0;
   __enable_threads();
   ASSERT_SYS(0, 0, pledge("stdio rpath", 0));
 }