Improve synchronization

- Fix bugs in kDos2Errno definition
- malloc() should now be thread safe
- Fix bug in rollup.com header generator
- Fix open(O_APPEND) on the New Technology
- Fix select() on the New Technology and test it
- Work towards refactoring i/o for thread safety
- Socket reads and writes on NT now poll for signals
- Work towards i/o completion ports on the New Technology
- Make read() and write() intermittently check for signals
- Blinkenlights keyboard i/o so much better on NT w/ poll()
- You can now poll() files and sockets at the same time on NT
- Fix bug in appendr() that manifests with dlmalloc footers off

libc/sock/bind.c

@@ -62,6 +62,6 @@ int bind(int fd, const void *addr, uint32_t addrsize) {
   } else {
     rc = einval();
   }
-  STRACE("bind(%d, %s) -> %d% m", fd, __describe_sockaddr(addr, addrsize), rc);
+  STRACE("bind(%d, %s) -> %d% lm", fd, __describe_sockaddr(addr, addrsize), rc);
   return rc;
 }