[GHC] #8787: compiler/ghc.mk: restore GhcHcOpts variable handling

[GHC]

#8787: compiler/ghc.mk: restore GhcHcOpts variable handling
-------------------------------------+------------------------------------
        Reporter:  slyfox            |            Owner:  thoughtpolice
            Type:  bug               |           Status:  patch
        Priority:  high              |        Milestone:  7.10.1
       Component:  Compiler          |          Version:  7.6.3
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
-------------------------------------+------------------------------------
Changes (by slyfox):

 * status:  new => patch


--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8787#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler