[GHC] #15877: --flavour=quick followed by --flavour=prof fails

[GHC]

#15877: --flavour=quick followed by --flavour=prof fails
-------------------------------------+-------------------------------------
           Reporter:  mpickering     |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.6.3
          Component:  Build System   |           Version:  8.6.2
  (Hadrian)                          |
           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:
-------------------------------------+-------------------------------------
 Starting from a clean tree I first built successfully with
 `--flavour=quick`, I then changed to `--flavour=prof` and the build failed
 as follows:

 {{{
 /root/ghc/_build/stage1/rts/build/libCffi_p.a: copyFile: does not exist
 (No such file or directory)
 shakeArgsWith    0.010s    0%
 Function shake   0.435s    0%
 Database read    0.670s    0%
 With database    0.035s    0%
 Running rules  123.401s   99%  =========================
 Total          124.551s  100%
 Error when running Shake build system:
   at src/Rules.hs:(32,19)-(45,17):
   at src/Rules.hs:45:5-17:
 * Depends on: _build/stage1/lib/package.conf.d/rts-1.0.conf
 * Raised the exception:
 ExitFailure 1
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15877>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler