ports/184039: Mk/Scripts: fix working with blanks in filenames, handle missing variables

[mandree at FreeBSD.org]

Synopsis: Mk/Scripts: fix working with blanks in filenames, handle missing variables

Responsible-Changed-From-To: freebsd-ports-bugs->portmgr
Responsible-Changed-By: mandree
Responsible-Changed-When: Sun Nov 17 21:36:08 UTC 2013
Responsible-Changed-Why: 
assign to maintainer (portmgr)

http://www.freebsd.org/cgi/query-pr.cgi?pr=184039