Conditionalization of local-nicknames

[Yehouda]

trivial-extensible-sequences/fallback.lisp

Line 9 in 71944f7

#+(or abcl ccl clasp ecl sbcl)

The local-nicknames is conditionalize, but the local nickname is used later in the file, so implementations which are not in the conditionalization list will error anyway. the way it is now means that other implemnations that do have local-nicknames (example: lispworks 8) also error without a reason.

I think just removing the conditionalization is the best solution, so implementations without local-nicknames will error at that point.