Revert "rts: Suppress unused gcc_clear_cache warning"
Revert "rts: Suppress unused gcc_clear_cache warning"

This reverts commit d1d3e98443cf263ef09253e2478e3e638e174e0d.

ezyang/ghc,ezyang/ghc,shlevy/ghc,ezyang/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,shlevy/ghc,shlevy/ghc,sdiehl/ghc,sdiehl/ghc,shlevy/ghc,ezyang/ghc,shlevy/ghc,ezyang/ghc,sdiehl/ghc,ezyang/ghc,sdiehl/ghc,shlevy/ghc,ezyang/ghc,shlevy/ghc