dropWhileEndLE breakage

[David Feuer]

Simon Peyton Jones asked
> What's going on here?   No other library module defines this function, except in Cabal!
> Simon

That was my fault; I'm very sorry. I had added that function (similar
to Data.List.dropWhileEnd, but not the same) to
compiler/utils/Util.lhs and to another module that used it, and then
forgot it was not available in libraries/base/GHC/.  Since neither
Phab nor I run Windows, there was little hope of catching the mistake
before it went out. I believe Joachim Breitner has fixed the problem
now by using Data.List.dropWhileEnd to construct that error
message—the difference in behavior doesn't matter there.

David Feuer