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/intrin/__getenv.c

@@ -22,7 +22,7 @@
 #define ToUpper(c) \
   (IsWindows() && (c) >= 'a' && (c) <= 'z' ? (c) - 'a' + 'A' : (c))
 
-dontasan struct Env __getenv(char **p, const char *k) {
+dontasan privileged struct Env __getenv(char **p, const char *k) {
   char *t;
   int i, j;
   for (i = 0; (t = p[i]); ++i) {