I don't know the official policy, but anecdotally, I won with an entry that used libperl back in 2000: http://www.ioccc.org/years.html#2000_dlowe
Aside: history... Larry Wall wrote the original Perl in 1986-87, the same two successive years he won the IOCCC. I hope this program helps you to realize that this was no fluke - that Perl and Obfuscation are as inseparable as, say, camels and humps.