arc-linters: Add linting of #ifdef x and #if defined x
arc-linters: Add linting of #ifdef x and #if defined x

Reviewers: austin, erikd

Reviewed By: erikd

Subscribers: rwbarton, thomie, erikd

Differential Revision: https://phabricator.haskell.org/D3423

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