rts: remove unused functions, fix validate on OS X
rts: remove unused functions, fix validate on OS X

After a toolchain update, Clang is no longer appreciative of the fact
these are unused, thanks to -Werror during validate.

Signed-off-by: Austin Seipp <7ea35d812706d9213868749011af1ed4fa2f6aa0@well-typed.com>
(cherry picked from commit 7ef3f0d6dbd54d9e58fb6ab1f2db322bc8fac37a)

hferreiro/replay,lukexi/ghc-7.8-arm64,hferreiro/replay,hferreiro/replay,lukexi/ghc-7.8-arm64,hferreiro/replay,hferreiro/replay,lukexi/ghc-7.8-arm64,lukexi/ghc-7.8-arm64,hferreiro/replay,lukexi/ghc-7.8-arm64,hferreiro/replay