Hey all, I"ve a WIP patch https://ghc.haskell.org/trac/ghc/ticket/8683 for making it easy to separately specify the CPP program command and associated flags in the ghc settings file. The haskell code part, for handling the dynflags / parsing the settings file etc tests out fine, i'm a bit stumped on how to get autoconf /m4 to work correctly for instantiating the desired values into the settings.intemplate though! (which happens at configure time) any help / wisdom? thanks! -Carter