[GHC] #12870: Allow completely disabling +RTS options parsing

[GHC]

#12870: Allow completely disabling +RTS options parsing
-------------------------------------+-------------------------------------
        Reporter:  nh2               |                Owner:  AndreasK
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by AndreasK):

 I would suggest adding at least two new flags to `rtsopts=`.

 * One to disable all parsing of RTS flags except the ones included at
 compile time.
 * One to disable parsing of RTS flags passed via arguments but still allow
 parsing of arguments passed via ENVs.

 My suggestions would be to use `ignore` and `ignoreArgs` although I'm open
 to suggestions.

 I don't see a usecase for parsing argument RTS flags but ignoring ENV
 Flags but that would be a logical third option. (`ignoreENV`?)

 Although not sure how useful parsing only env is as well since it suffers
 from the same problem of applying RTS flags where one might not have
 intended to.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12870#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler