Bug#718280: libev-perl: forcing of EV_EPOLL=1 leads to FTBFS on non-linux architectures

[Petr Salinger]

> I've now played around with 2 patches, one using this approach,the
> other using Devel::CheckLib. Both lead to the same result and work
> (on linux/amd64).

Both works also for kfreebsd-amd64.
I guess that Devel::CheckLib is the standard one, therefore prefered.
Just do not forget to add libdevel-checklib-perl into build-depends,
as without it fails ;-)

Petr