[GHC] #11268: Extend ghc environment file features

[GHC]

#11268: Extend ghc environment file features
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        Reporter:  hvr               |                Owner:  duncan
            Type:  feature request   |               Status:  patch
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1668
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"aa699b94e3a8ec92bcfa8ba3dbd6b0de15de8873/ghc"
 aa699b94/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="aa699b94e3a8ec92bcfa8ba3dbd6b0de15de8873"
 Extend ghc environment file features

 A set of changes to enable local ghc env files to be useful for tools
 like cabal. Ultimately it will allow cabal to maintain a ghc env file so
 that users can simple run ghc or ghci in a project directory and get the
 expected environment of the project.

 Change the name of .ghc.environment files to include the platform and
 ghc version, e.g. .ghc.environment.x86_64-linux-7.6.3, since their
 content is version specific. Strictly speaking this is not backwards
 compatible, but we think this feature is not widely used yet.

 "Look up" for a local env file, like the behaviour of git/darcs etc. So
 you can be anywhere within a project and get the expected environment.

 Don't look for local env files when -hide-all-packages is given.

 Extend the syntax of env files to allow specifying package dbs too.

 Test Plan:
 Currently completely untested. Compiles, that is all.
 Sorry, have to disappear for the hols.

 Reviewers: hvr, ezyang, austin, bgamari

 Reviewed By: ezyang, bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D1668

 GHC Trac Issues: #11268
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11268#comment:4>
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