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

tool/net/redbean.c

@@ -24,6 +24,7 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/math.h"
 #include "libc/calls/sigbits.h"
+#include "libc/calls/strace.internal.h"
 #include "libc/calls/struct/dirent.h"
 #include "libc/calls/struct/flock.h"
 #include "libc/calls/struct/rusage.h"
@@ -1187,11 +1188,7 @@ static void KillGroupImpl(int sig) {
 }
 
 static void KillGroup(void) {
-  if (IsWindows()) {
-    KillGroupImpl(SIGINT);
-  } else {
-    KillGroupImpl(SIGTERM);
-  }
+  KillGroupImpl(SIGTERM);
 }
 
 static void WaitAll(void) {