[GHC] #15982: Hadrian's `--configure` flag is broken on Windows

[GHC]

#15982: Hadrian's `--configure` flag is broken on Windows
-------------------------------------+-------------------------------------
           Reporter:  snowleopard    |             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:
-------------------------------------+-------------------------------------
 For some reason I can no longer use Hadrian's `--configure` flag. When I
 use it, the configuration step fails with the following obscure error:

 {{{
 rm: cannot remove '.MTREE': No such file or directory
 }}}

 This is certainly caused by this line in `configure.ac`:

 https://github.com/ghc/ghc/blob/93e86d6103757b43017535c92bc6970e9e2315a5/configure.ac#L358

 It's unclear what should be done in this case.


 Here is the command line I use to invoke Hadrian:

 {{{
 hadrian\build --configure -j --flavour=quickest --integer-simple
 }}}

 When I run the configure script manually from the MinGW shell, it works
 fine.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15982>
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