Provides enhancements in the functions code:--
* `ask' won't display empty parentheses for a zero
length default response spec.
* `isyes' will accept any case insensitive
abbreviation for `yes', to indicate an affirmative input.
Fixes the following defects:--
* `portmaker' is made executable, for users cross
building on UNIX or GNU/Linux hosts.
* `PORTPATH' is eval'ed, in case user wants something
rooted at `$HOME', or similar.
* some minor typos in `portmaker.sh' corrected.