Allow overriding the ghc compiler used
Allow overriding the ghc compiler used

… via a GHC make variable.

yiannist/ganeti,grnet/snf-ganeti,onponomarev/ganeti,dimara/ganeti,ganeti/ganeti,leshchevds/ganeti,mbakke/ganeti,leshchevds/ganeti,yiannist/ganeti,apyrgio/ganeti,apyrgio/snf-ganeti,apyrgio/ganeti,bitemyapp/ganeti,andir/ganeti,ganeti/ganeti,leshchevds/ganeti,onponomarev/ganeti,apyrgio/snf-ganeti,andir/ganeti,andir/ganeti,mbakke/ganeti,yiannist/ganeti,ganeti-github-testing/ganeti-test-1,ganeti-github-testing/ganeti-test-1,grnet/snf-ganeti,ganeti/ganeti,dimara/ganeti,bitemyapp/ganeti,mbakke/ganeti