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/mkfifo.c

@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
+#include "libc/calls/strace.internal.h"
 #include "libc/dce.h"
 #include "libc/intrin/asan.internal.h"
 #include "libc/nt/ipc.h"
@@ -33,11 +34,15 @@
  * @asyncsignalsafe
  */
 int mkfifo(const char *pathname, unsigned mode) {
-  /* TODO(jart): Windows? */
-  if (IsAsan() && !__asan_is_valid(pathname, 1)) return efault();
-  if (IsLinux()) {
-    return sys_mknod(pathname, mode | S_IFIFO, 0);
+  // TODO(jart): Windows?
+  int rc;
+  if (IsAsan() && !__asan_is_valid(pathname, 1)) {
+    rc = efault();
+  } else if (IsLinux()) {
+    rc = sys_mknod(pathname, mode | S_IFIFO, 0);
   } else {
-    return sys_mkfifo(pathname, mode);
+    rc = sys_mkfifo(pathname, mode);
   }
+  STRACE("mkfifo(%#s, %#o) → %d% m", pathname, mode, rc);
+  return rc;
 }