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

examples/forkrand.c

@@ -33,8 +33,6 @@ dontinline void dostuff(const char *s) {
 
 int main(int argc, char *argv[]) {
   int rc, child, wstatus;
-  /* puts(_gc(xiso8601ts(NULL))); */
-  PrintMemoryIntervals(2, &_mmi);
   CHECK_NE(-1, (child = fork()));
   if (!child) {
     /* child process */