GhcMake: Clang/ASSERT fix
GhcMake: Clang/ASSERT fix

Test Plan: Build with clang

Reviewers: thomie, rwbarton, austin, bgamari

Reviewed By: bgamari

Differential Revision: https://phabricator.haskell.org/D1977

(cherry picked from commit 5e2605e4e740d46014eaf3eb2b2b2e05a43bb8b2)

GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc