[GHC] #5218: Add unpackCStringLen# to create Strings from string literals

[GHC]

#5218: Add unpackCStringLen# to create Strings from string literals
-------------------------------------+-------------------------------------
        Reporter:  tibbe             |                Owner:  thoughtpolice
            Type:  feature request   |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.0.3
      Resolution:                    |             Keywords:  strings
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #5877 #10064      |  Differential Rev(s):  Phab:D2443
  #11312, #9719                      |
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by simonpj):

 > My understanding of this problem is that we want a way to tell ghc how
 to compile literals.

 That's the bit under "Haskell" in comment:86.  But we still need to
 compile them into something.  But what?  That's the bit under "Core" in
 comment:86.  Once we have the Core bit settled we can return to the
 Haskell bit.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5218#comment:88>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler