Note that 5.8.1 was the perl that was binary incompatible.. It was incompatible to 5.8.0. That was repaired in 5.8.2. Thus I would guess that many people dont bother to test much with 5.8.1, and go straight to 5.8.2 and above. You might look to see if Fedora/OSX etc have an upgrade to 5.8.2.
Indeed FC1 has an upgrade to 5.8.2 (released sometime before November last year), and also to 5.8.3 (as of March 25 this year). You might want to check your settings on yum / up2date to see why you're not getting those...