svn commit: r457360 - head/Mk/Uses

[Alexey Dokuchaev]

On Wed, Dec 27, 2017 at 01:47:35PM +0100, Jan Beich wrote:
> Alexey Dokuchaev <danfe at FreeBSD.org> writes:
> > On Wed, Dec 27, 2017 at 10:41:30AM +0000, Jan Beich wrote:
> >
> >> New Revision: 457360
> >> URL: https://svnweb.freebsd.org/changeset/ports/457360
> >> 
> >> Log:
> >>   Update USES=compiler:c++14-lang to Clang 5.0 on FreeBSD 10
> >
> > What was the reason behind this change?
> 
> Do we really need a reason to update? ;) Here's an incomplete list:

I was mostly concerned because LLVM ports take quite some time to build
and package, so I always worry when this requirement bumps.  Providing
a little technical background behind changes occurring in important and
heavy infrastructure port(s) would help stupid people like myself to
understand the current state of affairs and direction better.

> - Many projects don't care about old compilers; Clang support is
>   usually driven by OS X and ASan users
> - Clang 4.0 is no longer maintained upstream; unlike GCC maintenance
>   cycles are very short (around half a year)
> - FreeBSD 11.2 (aka /stable/11) and FreeBSD 12.0 (aka /head) already
>   use Clang 5.0 in base
> - devel/llvm50 can build more ports with -flto=thin -fuse-ld=lld
> - Better C++17 support but still incomplete due to old libc++ in base
> - Mesa switched to llvm50 in r457264 -> less build dependencies
> - www/firefox switched to llvm50 in r457267 -> less build dependencies
> 
> > Why on FreeBSD 10, what about 11 and 12-CURRENT?
> 
> USES=compiler:c++14-lang is nop for FreeBSD 11 or later because Clang is
> new enough to support C++14. To be removed after FreeBSD 10.* reaches EOL.
> Architectures stuck with GCC don't differentiate between C++11 and C++14
> capable compiler.

Thank you, that was quite helpful, I appreciate the taken time to write
these things up.

./danfe