[m-rev.] for review: Replace boehm_gc/extra/if_not_there.c with shell script.

[Julien Fischer]

Hi Peter,

On Tue, 25 Aug 2015, Peter Wang wrote:

> When building Mercury natively with MinGW-w64 x86_64 under MSYS2
> I saw that some process would crash in the boehm_gc directory:
>
>  ./if_not_there mach_dep.o /bin/sh [snip]/../scripts/mgnuc [snip] ./mach_dep.c
>  ^^^^Starting command^^^^
>
>  This application has requested the Runtime to terminate it in an unusual way.
>  Please contact the application's support team for more information.
>
> The same command would not crash if I ran it manually in the shell,
> though it did return to the shell before completing.
>
> Replacing if_not_there.c by a shell script avoids the problem, such that
> I was able to continue and build the rest of the compiler.  We require a
> working shell on all platforms that we support, unlike Boehm GC upstream,
> so I'm going to leave it at that.
>
> boehm_gc/extra/if_not_there.sh:
> 	Add shell script that mimics if_not_there.c.
>
> boehm_gc/Makefile.direct:
> 	Use if_not_there.sh in place of the compiled version of
> 	if_not_there.c.

That's fine.

Julien.