multimedia/ffmpeg build fails on 9.2-STABLE and perl-5.18

[Marko Cupać]

After rebuilding world and kernel to 9.2-STABLE amd64 r256096 I upgraded
perl to perl-5.18.1_1, and consequently initiated 'in place' update of
all my ports with portmaster -afd. It failed on multimedia/ffmpeg with
error described here:

http://www.freebsd.org/cgi/query-pr.cgi?pr=181516

Provided patch did not work for me so I created another one. I've just put
it to /usr/ports/multimedia/ffmpeg/files and after that port compiles fine.

My patch is attached.

-- 
Marko Cupać