[GHC] #4829: build does not respect --with-gcc option

[GHC]

#4829: build does not respect --with-gcc option
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    Reporter:  gwright           |        Owner:                     
        Type:  bug               |       Status:  new                
    Priority:  normal            |    Milestone:                     
   Component:  Build System      |      Version:  7.0.1              
    Keywords:                    |     Testcase:                     
   Blockedby:                    |   Difficulty:                     
          Os:  Unknown/Multiple  |     Blocking:                     
Architecture:  Unknown/Multiple  |      Failure:  Building GHC failed
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Comment(by gwright):

 Replying to [comment:1 simonmar]:
 > We should fix `--with-gcc`.  It can't be entirely broken, because we use
 the same mechanisms on Windows to use the inplace mingw gcc, and I'm
 fairly sure at least on some of my machines I don't have mingw installed
 in the usual place.
 >
 Yes, the `--with-gcc` option mostly works but there are a few places where
 it fails.

 > Using `SRC_HC_OPTS` is probably not the right thing, because those
 options will be passed to the bootstrap compiler too.  That would normally
 be a strange thing to do, because the bootstrap compiler is supposed to
 generate working executables by itself, with no special options.

 OK, I'll patch so that it's not necessary to mess with `SRC_HC_OPTS`.
 This does set an implicit policy, i.e., that the options to substitute
 preprocessors/compilers/assembers/linker shouldn't be used when building
 ghc.  I've no problem with that, but it should probably be written down on
 the wiki.  Perhaps just saying that switching compilers should be done
 with the `--with-gcc` option only, and if you needed to set anything else,
 it's a bug and should be reported.

 You can close #4821 as invalid and point people to this bug instead.  If
 `SRC_HC_OPTS` should never have a `-pgmP` option, we won't have a conflict
 between the makefile supplied preprocessor options and any explicit ones.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4829#comment:2>
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