[m-rev.] for post-commit review: report unqualified types in .int files

[Peter Wang]

On Sat, 10 Oct 2020 19:00:47 +1100 "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> 
> 2020-10-10 18:45 GMT+11:00 "Dirk Ziegemeyer" <dirk at ziegemeyer.de>:
> > mercury_memory_handlers.c:64:6: error: "MR_HAVE_SIGINFO defined but don't know how to get it"
> >     #error "MR_HAVE_SIGINFO defined but don't know how to get it"
> >      ^
> > mercury_memory_handlers.c:83:6: error: "MR_HAVE_SIGINFO defined but don't know how to get it"
> >     #error "MR_HAVE_SIGINFO defined but don't know how to get it"
> >      ^
> > mercury_memory_handlers.c:270:41: error: use of undeclared identifier 'bus_handler'
> >     MR_setup_signal(SIGBUS, (MR_Code *) bus_handler, MR_TRUE,
> >                                         ^
> > mercury_memory_handlers.c:273:42: error: use of undeclared identifier 'segv_handler'
> >     MR_setup_signal(SIGSEGV, (MR_Code *) segv_handler, MR_TRUE,
> 
> It seems that mercury_memory_handlers.c expects MR_HAVE_SIGINFO to be set
> in a small set of circumstances, as indicated by the #ifs nested inside #ifdef MR_HAVE_SIGINFO,
> but configure.ac sets MR_HAVE_SIGINFO in more circumstances than that. It looks like
> mercury_memory_handlers.c was not updated when configure.ac was.
> 
> Peter, you wrote most of the configure.ac lines that mention MR_HAVE_SIGINFO,
> and you also touched them most recently, so could you please have a look at this?

I only reformatted those lines two years ago.

I expect what's happening is this:

  - sigaction should always be found, so MR_HAVE_SIGINFO is defined by
    configure.ac line 1577

  - sigcontext/sigcontext_struct seems to be some Linux specific thing,
    so I don't think it ever would have been defined on MacOS.
    (That code might never be used on any modern Linux either,
    so could be deleted? Will need to confirm later.)

  - MR_HAVE_SIGINFO_T is defined on line 1816 but the test that enables
    it looks pretty complicated and may have broke with the MacOS update.

Peter