Check for the existence of CODESET, not that it's a truthy value.
Created originally on Bitbucket by HawkOwl (Amber Brown)
Was already merged in Bitbucket before import, marked as merged by the import user
CODESET is set from langinfo.h -- the value on Linux is 14, but the value on BSD is 0, so this should have prevented PyPy from ever working on FreeBSD.