ports/170490: fix port: math/proofgeneral

[bdrewery at FreeBSD.org]

Synopsis: fix port: math/proofgeneral

Responsible-Changed-From-To: freebsd-ports-bugs->bdrewery
Responsible-Changed-By: bdrewery
Responsible-Changed-When: Wed Aug 8 21:28:48 UTC 2012
Responsible-Changed-Why: 
I'll take it.

http://www.freebsd.org/cgi/query-pr.cgi?pr=170490