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/calls/nanosleep-nt.c

@@ -49,10 +49,8 @@ textwindows noinstrument int sys_nanosleep_nt(const struct timespec *req,
     } else {
       slice = ms;
     }
-    if (!__time_critical) {
-      STRACE("SleepEx(%u, true)", slice);
-    }
     if (SleepEx(slice, true) == kNtWaitIoCompletion) {
+      STRACE("IOCP TRIGGERED EINTR");
       rc = eintr();
       break;
     }