Cabal revisions of stm-2.4

Hackage metadata revisions edit the .cabal file after upload; each diff below is one revision.

 name:		stm version:        2.4+x-revision: 1 license:	BSD3 license-file:	LICENSE maintainer:	libraries@haskell.org     Control.Monad.STM   other-modules:     Control.Sequential.STM-  build-depends: base < 5, array+  build-depends: base < 4.12, array < 0.6   if flag(base4)     build-depends: base >=4     cpp-options:   -DBASE4