Re: [Caml-list] use cc instead of gcc as default C compiler?

[Christopher Zimmermann <christopher@gmerlin.de>]

On 2017-10-25 Adrien Nader <adrien@notk.org> wrote:
> Hi,
> 
> On Wed, Oct 25, 2017, Christopher Zimmermann wrote:
> > >> My Problem is that custom OCaml builds, especially the ones done  
> > >through opam will use gcc and therefore fail to build projects with not
> > >so modest requirements. At the moment I'm just wondering at which level
> > >in the toolchain this neuds fixing. OCaml configure, opam-repository or
> > >opam source?
> > >
> > >Could you elaborate on that « therefore fail to build projects with not
> > >so modest requirements » ?  
> > 
> > In my case it is core_kernel v0.9 which fails on OpenBSD gcc 4.2.1 because it uses -mpopcnt, while it compiles just fine with OpenBSD cc clang 4.0.0.  
> 
> I believe there are several things to change. I outline my thoughts
> below; I've sorted them by due date:
> 
> 1- (overdue): Openbsd should stop shipping GCC 4.2: it's ten years old
> and unmaintained. *TEN* years. It shouldn't be a surprise it starts
> causing issues. The very reason 'gcc' has been used by ocaml instead of
> 'cc' was to avoid bad compilers on old systems and now openbsd is
> re-creating similar issues, only with a different twist.

OpenBSD, FreeBSD, darwin all switched to clang because of licensing
issues. They won't integrate gcc >4.2.1 into the base system because it
is GPLv3. They do however ship a recent clang, called 'cc'. 'gcc' 4.2.1
is only included for a transition period on OpenBSD base system.

recent gcc compilers are installable from ports. They are called 'egcc'.

> 2- (easy, compatible): OCaml's configure script should probably fallback
> to clang if GCC isn't found.

It already does that.

> That way, with openbsd not shipping GCC 4.2 anymore

This may happen some time, but you might install a recent gcc from
ports then, which would confuse the build script.

> clang would be automatically selected. I assumue ports ship a
> modern GCC and installing this one would still result in a working
> setup. Unsurprisingly, this is the step where you're invited to
> contribute: it should really be a small change. My only concern is that
> I seem to recall past discussions related to detecting clang but not
> their outcome.

As I wrote above this is already the current behaviour.

> 3- (longer term): I know that there has been some work on a replacement
> of the configure script with something autoconf-based (and before anyone
> complains, this doesn't include automake nor libtool). I don't know the
> current status of this work however.

Still I would pledge to use 'cc' as default in such a new configure
script.


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