Revert the ivdformat probing

Revert the ivdformat probing

Devel::CheckLib isn't really capable of probing standard library
functions - it wants a library name to probe for and the standard
library functions aren't always loaded from something called
"libc.ext".

Due to the structure of Devel::CheckLib if you don't provide a library
name to probe for the running code checks are skipped entirely,
passing by default.

So remove this for now.

I have a work-in-progress branch with a modified Devel::CheckLib, but
since I push Devel::CheckLib changes out to the JPEG, TIFF, etc dists
it would mean meaningless new releases for those too.  Meaningless
because the changes to D::CL would have no effect on them beyond a
version bump.