[m-rev.] for review: Update README.MinGW regarding MSYS2 and x86_64.

[Julien Fischer]

On Fri, 28 Aug 2015, Peter Wang wrote:

> On Fri, 28 Aug 2015 15:25:16 +1000 (AEST), Julien Fischer <jfischer at opturion.com> wrote:

>> On Tue, 25 Aug 2015, Peter Wang wrote:
>>
>>> If anyone would care to try to reproduce the build on i686 or x86_64,
>>> that would be great.
>>
>> The only additional issue I encountered is that on my system there are
>> three MSYS2 items under the start menu:
>>
>>      * MinGW-w64 Win32 Shell
>>      * MinGW-w64 Win64 Shell
>>      * MSYS2
>
> I'll clarify that.

One of the effects of the those versions is that the string returned by
config.guess differs:

     MinGW-w32 Win32 Shell ==> x86_64-pc-mingw32
     MinGW-w64 Win64 Shell ==> x86_64-pc-mingw64
     MSYS2                 ==> x86_64-pc-msys

>> If you select the last one then GCC doesn't appear to be in the PATH
>> by default.  I also had to apply the following patch:
>>
>> --------------------
>>
>> diff --git a/boehm_gc/Makefile.direct b/boehm_gc/Makefile.direct
>> index 23c12bb..58e0cd7 100644
>> --- a/boehm_gc/Makefile.direct
>> +++ b/boehm_gc/Makefile.direct
>> @@ -235,7 +235,7 @@ all: gc.a gctest
>>   # Mercury-specific: clear DESTDIR
>>   $(AO_INSTALL_DIR):
>>          CC="$(CC)" AR="$(AR)" RANLIB="$(RANLIB)" MAKE=$(MAKE) DESTDIR= \
>> -          $(srcdir)/build_atomic_ops.sh --host=$(FULLARCH)
>> +          $(srcdir)/build_atomic_ops.sh --build=$(FULLARCH) --host=$(FULLARCH)
>>
>>   LEAKFLAGS=$(CFLAGS) -DFIND_LEAK
>>
>> --------------
>>
>> I'm not quite sure *why* I had I to do that, although I suspect the
>> reason is that the versions of config.guess and config.sub under the
>> boehm_gc directory are *very* old (from ~2009).
>
> I might have updated them in my workspace without knowing.
> We can update the files in the boehm_gc and libatomic_ops directories
> to the same versions we have in the root directory.

I suggest that you update all of them (top-level directory, boehm_gc
and boehm_gc/libatomic_ops) to the latest version.

Julien.