[m-rev.] for review: improve support for MSYS2 builds

[Peter Wang]

On Fri, 24 Jan 2020 13:58:33 +1100 (AEDT), Julien Fischer <jfischer at opturion.com> wrote:
> 
> For review by Peter.
> 
> This replaces my diff from yesterday; it preserves the possibility
> of using MinGW-w64 cross-compiler.
> 
> -------------------------------------
> 
> Improve support for MSYS2 builds.
> 
> MSYS2 provides a POSIX like environment and package manager for Windows.
> It packages up the MinGW-w64 port of GCC.  (MSYS2 is separate from the
> original MSYS.)

Can you add your explanation of the MinGW, MinGW-w64, MSYS and MSYS2
projects to the top of README.MinGW, and the host triplets involved?

> 
> Make it possible to build Mercury under MSYS2 with the MinGW-w64 GCC
> without having to resort to cross compilation.
> 
> configure.ac:
>      Recognise the x86_64-pc-mingw* architecture returned by config.guess
>      under MSYS2.
> 
>      If we are building the MSVC port under MSYS2, set up the flags for
>      threads appropriately.
> 
> scripts/ml.in:
>      Pass libraries to the linker correctly for static linking on all the
>      different MinGW configurations.
> 
> Julien.
> 

> diff --git a/README.MinGW b/README.MinGW
> index 57df999..d6a5387 100644
> --- a/README.MinGW
> +++ b/README.MinGW
> @@ -98,16 +98,22 @@ To build the source distribution under MSYS follow these steps:
>       path with a drive letter (except use `/' instead of `\').
>       Do not use a path like `/mercury', because that
>       will be interpreted differently by the MSYS shell than by the generated
> -    executables, resulting in a broken installation. 
> +    executables, resulting in a broken installation.
> 
> -    If you are using the MSYS or MSYS2 shell with MinGW-w64 then you must also
> -    invoke configure with the following option:
> +    If you are using the MSYS shell with MinGW-w64 then you must also invoke
> +    configure with the following option:
> 

... using the MSYS shell (not the MSYS2 shell) ...

>          --host=x86_64-w64-mingw32
> 
>       This will cause mmake to use the MinGW-w64 tool chain.  Ensure that the
>       MinGW-w64 tools are in your PATH before running configure.
> 
> +    If you are using the MSYS2 shell then you need to launch it in either
> +    the "MSYS2 MinGW 32-bit" mode or the "MSYS2 MinGW 63-bit mode" to build

Move the first end quote to after "mode".

63-bit

> +    a 32- or 64-bit Mercury system respectively.  You do *not* need to pass
> +    the --host=x86_64-w64-mingw32 option to configure on MSYS2; if you do
> +    you will get a 64-bit compiler.
> +

Replace the last sentence with something like:

    You do not need to pass the --host option to configure; it will
    detect the 32-bit or 64-bit MSYS2 environment you are running in.

?

> diff --git a/configure.ac b/configure.ac
> index 281baef..3e7e10c 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -3277,12 +3277,22 @@ case "$host" in
>           esac
>           ;;
> 
> -    *-w64-mingw*)
> -        CFLAGS_FOR_THREADS="$WIN32_GC_THREADLIB"
> -        BOEHM_CFLAGS_FOR_THREADS="-DGC_THREADS $WIN32_GC_THREADLIB"
> -        THREAD_LIBS="-lpthread"
> -        ENABLE_BOEHM_THREAD_LOCAL_ALLOC="-DTHREAD_LOCAL_ALLOC"
> -        ENABLE_BOEHM_PARALLEL_MARK="-DPARALLEL_MARK"
> +    *-w64-mingw*|x86_64-pc-mingw*)
> +        THREAD_LIBS=""
> +        case "$mercury_cv_cc_type" in
> +            msvc)
> +                CFLAGS_FOR_THREADS="-DGC_THREADS -MD"
> +                LDFLAGS_FOR_THREADS="-MD"
> +                LD_LIBFLAGS_FOR_THREADS="-MD"
> +                ;;
> +            *)
> +                CFLAGS_FOR_THREADS="$WIN32_GC_THREADLIB"
> +                BOEHM_CFLAGS_FOR_THREADS="-DGC_THREADS $WIN32_GC_THREADLIB"
> +                THREAD_LIBS="-lpthread"
> +                ENABLE_BOEHM_THREAD_LOCAL_ALLOC="-DTHREAD_LOCAL_ALLOC"
> +                ENABLE_BOEHM_PARALLEL_MARK="-DPARALLEL_MARK"
> +                ;;
> +        esac
>           ;;
> 

Ok. I think we can merge this case with the preceding case for
i*86-pc-mingw*, but commit this first.

Peter