[GHC] #15576: Hadrian puts its build tree in the wrong place

[GHC]

#15576: Hadrian puts its build tree in the wrong place
-------------------------------------+-------------------------------------
           Reporter:  simonpj        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.4.3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 I have a source tree in my slow, network-mounted backed-up filestore
 `/home/simonpj/ghc`, and a separate link-tree in my fast, physically-
 connected, non-backed up filestore `/playpen/ghc`.  Every file in
 `/playpen/ghc` is a symlink to the corresponding source file in
 `/home/simonpj/ghc`.

 But when I do
 {{{
 $ cd /playpen/ghc
 $ hadrian/build.sh -c -j4 --flavour=quick
 }}}
 I find a new `_build` director in `/home/simonpj/ghc`.  This is bad!  It
 should be in `/playpen/ghc`.  Otherwise (a) it's slower, (b) it creates
 backup churn and (c) as it happens, I ran out of space on the backed-up
 filestore.

 Can this be fixed?  It's a bad Hadrian shortcoming.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15576>
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