[GHC] #9720: libffi compilation does not use bundled g++ on Windows

[GHC]

#9720: libffi compilation does not use bundled g++ on Windows
-------------------------------------+-------------------------------------
       Reporter:  gintas             |                   Owner:
           Type:  bug                |                  Status:  new
       Priority:  normal             |               Milestone:
      Component:  Build System       |                 Version:  7.8.3
       Keywords:                     |        Operating System:  Windows
   Architecture:  Unknown/Multiple   |         Type of failure:
     Difficulty:  Unknown            |  None/Unknown
     Blocked By:                     |               Test Case:
Related Tickets:                     |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
 Building GHC fails on Windows (at least on mingw32) if there is no host
 g++ compiler available. The cause seems to be that configure script looks
 for a C++ compiler and fails to find one.

 Here's the invocation of the libffi configure script from the main build:

 cd libffi && \
      \
     cd build && \
 CC=C:/Users/Gintas/Downloads/msys32/home/Gintas/ghc/inplace/mingw/bin/gcc.exe
 \
 LD=C:/Users/Gintas/Downloads/msys32/home/Gintas/ghc/inplace/mingw/bin/ld.exe
 \
     AR=/usr/bin/ar \
 NM=C:/Users/Gintas/Downloads/msys32/home/Gintas/ghc/inplace/mingw/bin/nm.exe
 \
 RANLIB=C:/Users/Gintas/Downloads/msys32/home/Gintas/ghc/inplace/mingw/bin/ranlib.exe
 \
         CFLAGS=" -U__i686 -march=i686 -fno-stack-protector -w" \
         LDFLAGS="  -w" \
         "/bin/sh" ./configure \
 --prefix=C:/Users/Gintas/Downloads/msys32/home/Gintas/ghc/libffi/build/inst
 \
 --libdir=C:/Users/Gintas/Downloads/msys32/home/Gintas/ghc/libffi/build/inst/lib
 \
           --enable-static=yes \
           --enable-shared=no \
           --host=i386-unknown-mingw32

 Note that CC is overridden, but CXX is not. The configure script then
 looks for a C++ compiler and finds KCC, which is not even a compiler but a
 kerberos tool:

 checking for g++... no
 checking for c++... no
 checking for gpp... no
 checking for aCC... no
 checking for CC... no
 checking for cxx... no
 checking for cc++... no
 checking for cl.exe... no
 checking for FCC... no
 checking for KCC... KCC
 checking whether we are using the GNU C++ compiler... no
 checking whether KCC accepts -g... no
 checking dependency style of KCC... none

 This causes the configure script to fail later on.

 g++ is not actually used in the build (looks like it's only needed for one
 test case), passing in gcc for CXX seems to work fine.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9720>
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