[m-rev.] for review: Check availability of getopt() directly.

[Julien Fischer]

On Fri, 31 May 2019, Peter Wang wrote:

> configure.ac:
> Mmake.common.in:
>    Check for availability of getopt() in the C library,
>    setting the HAVE_GETOPT variable as appropriate.
>
>    Delete GETOPT_H_AVAILABLE variable.
>
> util/Mmakefile:
>    Use getopt() if available. This can be true even without getopt.h
>    as getopt() is declared in <unistd.h> according to POSIX.
>
> util/getopt.h:
>    Add a comment.

...


> diff --git a/util/Mmakefile b/util/Mmakefile
> index 8ccce6a91..d8e22ee08 100644
> --- a/util/Mmakefile
> +++ b/util/Mmakefile
> @@ -30,8 +30,10 @@ PROGS=mkinit mkinit_erl mdemangle mfiltercc info_to_mdb
> PROGFILENAMES=$(PROGS:%=%$(EXT_FOR_EXE))
> SRC=$(PROGS:%=%.c)
> 
> -# Only if getopt.h doesn't exist do we link in a version of getopt.
> -ifeq ("$(GETOPT_H_AVAILABLE)","no")
> +# Link in local copy of getopt() only if required.
> +# XXX The files in runtime/GETOPT may not compile cleanly with modern
> +# compilers. We should replace it with another implementation.

We need to replace them (certainly the one in runtime/mercury_getopt.c)
for licensing reasons anyway.

The diff is fine.

Julien.