bug fix: defaulting to the /share dir causes the PREFIX variable to be ignored

[Sam Trenholme]

> Alright, here's a diff patch for the ./build/install.location included
> in your v2.0.01 package of MaraDNS.

Looks good, but, again, it is better to use "-u" diffs,

http://www.maradns.org/faq.html#patch

- Sam