[tlbuild] Test failing on NetBSD

[Karl Berry]

The non-ASCII character in the test (0277) is intentional, although
admittedly we could just clear it and get on with life. 

But, maybe iscntrl() on netbsd is returning true for that character?
Whereas on other systems it's said to be true only for <040 or =0177.

Can you try changing that line to, say,
  if (*p <= 31 || *p == '\r' || *p == '\n' || *p == '\t')
and see if that helps?

(Let's ignore DEL, who cares.) --thanks, karl.