Small inconsistencies in configure checks

[Vitaly Chikunov]

On Sat, Dec 02, 2023 at 08:38:06PM +0000, Olly Betts wrote:
> On Sat, Dec 02, 2023 at 10:24:57PM +0300, Vitaly Chikunov wrote:
> > JFYI. I am not sure it's worth reporting but, when building 2.5.5 for ALT
> 
> Talking of small inconsistencies, 2.5.5 isn't a Xapian version...

Oh year that was libseccomp, since I build them both today. Xapian was
1.4.24. ;)

> 
> > I noticed small inconsistencies in configure output.
> > 
> > 1. xapian-binding:
> > 
> >   checking for /usr/bin/rdoc... no
> >   checking for rdoc... /usr/bin/rdoc
> > 
> > Looks curious but no problem since it's found anyway.
> 
> I think this is a bug but it's likely only a problem if you're
> overriding RUBY=/path/to/ruby but not overriding RDOC as well.
> 
> The aim is to try to use the rdoc which matches the Ruby interpreter
> found as a default (unless the user has explicitly overridden by
> running ./configure RDOC=/path/to/rdoc or similar), but it looks like
> the way that's currently being done doesn't actually work.  I'll fix
> that.
> 
> > 2. xapian-core when built with GCC:
> > 
> >   checking whether __builtin_add_overflow is declared... yes
> >   ...
> >   checking whether _addcarry_u64 is declared... no
> > 
> > There is actually _addcarry_u64 in GCC too, but it's in x86intrin.h
> > instead of intrin.h. This is no problem either, since it's superimposed
> > by __builtin_add_overflow anyway.
> 
> I think __builtin_add_overflow() is going to be as good an option (and
> possibly a better option where both are supported) so this doesn't seem
> a problem unless there's actually some platform with x86intrin.h but
> without both __builtin_add_overflow() and intrin.h.

Thanks!

> 
> Cheers,
>     Olly