Make improvements

- Improved async signal safety of read() particularly for longjmp()
- Started adding cancel cleanup handlers for locks / etc on Windows
- Make /dev/tty work better particularly for uses like `foo | less`
- Eagerly read console input into a linked list, so poll can signal
- Fix some libc definitional bugs, which configure scripts detected

libc/calls/setrlimit.c

@@ -97,3 +97,5 @@ int setrlimit(int resource, const struct rlimit *rlim) {
          DescribeRlimit(0, rlim), rc);
   return rc;
 }
+
+__weak_reference(setrlimit, setrlimit64);