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

[GHC]

#5218: Add unpackCStringLen# to create Strings from string literals
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        Reporter:  tibbe             |                Owner:  thoughtpolice
            Type:  feature request   |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.0.3
      Resolution:                    |             Keywords:
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                             |
       Wiki Page:                    |
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Comment (by bgamari):

 jscholl, I was speaking to phadej yesterday and he also sounded interested
 in looking at this problem. Regardless of what happens, this is a change
 to the user-facing interface provided by the compiler and consequently
 falls under the [[https://github.com/ghc-proposals/ghc-proposals|GHC
 proposal process]]. Do you think you could write a proposal explaining
 your approach?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5218#comment:75>
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