[m-rev.] for review: update to Boehm GC v8.2.4

[Julien Fischer]

On Tue, 11 Jul 2023, Julien Fischer wrote:

>>  Thanks. It looks like I made a mistake last year when preparing
>>  release-8_2-mercury-20221006-rc by losing the commit
>>  "Avoid linking with user32.dll on Windows." which does this:
>>
>>  diff --git a/misc.c b/misc.c
>>  index 99747ecd..239fc433 100644
>>  --- a/misc.c
>>  +++ b/misc.c
>>  @@ -34,6 +34,8 @@
>> #  endif
>> #  define NOSERVICE
>> #  include <windows.h>
>>  +/* Mercury-specific: avoid linking with user32.dll */
>>  +#define DONT_USE_USER32_DLL
>>  #endif
>>
>>  Should we:
>>  1. define NO_MSGBOX_ON_ERROR, which prevents calling MessageBox
>>     completely
>>  2. define DONT_USE_USER32_DLL, which prevents statically linking to
>>     user32.dll, but will try to look up MessageBox dynamically?
>
> I suggest the latter (i.e. put it back the way it was).  The message
> box is only used on a fatal error anyway.

Actually, I'm going to change my opinion and say we should do both.
Have a message box (which has to be dimissed by pressing a button)
during a bootcheck is irritating.

Julien.