[GHC] #8593: vector is being built even with `--no-dph`

[GHC]

#8593: vector is being built even with `--no-dph`
------------------------------------+-------------------------------------
       Reporter:  nomeata           |             Owner:
           Type:  feature request   |            Status:  new
       Priority:  low               |         Milestone:
      Component:  Build System      |           Version:  7.7
       Keywords:                    |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
------------------------------------+-------------------------------------
 I usually use `./sync-all --no-dph get` to speed up things a bit. But
 packages `vector`, `primitive` and `random` are still being pulled (by
 virtue of being submodules), and then built.

 It would be nice if the build system would build them only if
 `libraries/dph` is available, or have another way of making them optional.

 (Potentially obsolete once #8545 is done.)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8593>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler