cabal passes incorrect --host= when cross-compiling

[trofi]

Noticed today that ghc-HEAD now fails cross-compilation from linux to windows.

The cause is non-canonical for of the --host= passed by Cabal, likely caused by 5ef3478

Here is the reproducer:

cd ghc-HEAD
$ ./configure --target=x86_64-w64-mingw32
$ make
... <somewhere in base>
checking Haskell type for useconds_t... Word32
checking Haskell type for suseconds_t... configure: error: type not found

libraries/base/dist-install/build/config.log shows extra argument:

$ //home/slyfox/dev/git/ghc-mingw32/libraries/base/configure --with-compiler=ghc CFLAGS=-Wall     -Werror=unused-but-set-variable -Wno-error=inline LDFLAGS=   CPPFLAGS=    --host=x86_64-w64-mingw32 CC=/usr/lib/ccache/bin/x86_64-w64-mingw32-gcc --host=x86_64-windows

Note how --host is passed twice:

• --host=x86_64-w64-mingw32 (ok, the tools are expected to have this name)
• --host=x86_64-windows (bad, overrides tool names, directories and breaks $host match in https://github.com/ghc/ghc/blob/master/libraries/base/configure.ac#L19 ):

case $host in
    *mingw32*|*mingw64*|*cygwin*|*msys*)
        WINDOWS=YES;;
    *)
        WINDOWS=NO;;
esac

Cabal should pass --host= unmangled. Otherwise ${host}-<tool> toolchain tools would not detect correctly.

[angerman]

@hvr, @phadej, @bgamari shouldn't this be fixed for 8.8? Otherwise building ghc will just fail.

[nomeata]

I think I ran into this a few weeks ago… what might be the status of that?

[jneira]

I tried recently to build base in windows and i've got the same error.
I got base with cabal get base-4.14.3.0 and build it with cabal build --allow-boot-library-installs -finteger-simple.