Bump the minimal version required to compile DMD to 2.076.1

[Joakim]

On Sunday, 14 January 2018 at 19:22:11 UTC, Martin Nowak wrote:
> We've been through bootstrapping discussions a couple of times, 
> so let me repeat what was decided when we made the frontend 
> switch from C++ to D.
>
> - Other platforms are bootstrapped by cross-compilation.

Realistically, I'm not sure how this is supposed to work beyond 
the initial port.  As Thomas Mader pointed out earlier, most 
packaging systems expect to build from source, which right now 
means starting with the 2.067/2.068 C++ frontend and then porting 
every version needed up till the latest.

So under Seb's proposed scenario, 2.067, 2.076, and 2.078 would 
all need to be ported and integrated into their packaging system. 
If we bump it to 2.082 later, that becomes, 2.067, 2.076, 2.082, 
and the latest at the time, 2.085 or whatever.  This makes it 
more and more difficult for ports.

> - DMD must be compilable with the latest stable/major release 
> of dmd, ldc, and gdc.
>
>   To enforce this policy the Travis-CI test was set up.
>   Hopefully this original purpose of the Travis-CI hasn't been 
> forgotten in the meantime.

Yet the dmd and ldc CI, not sure about gdc, explicitly build with 
2.068 to make sure it's still working.  Maybe that's because gdc 
is still on 2.068, but it wasn't clear that that's the reason.

> - No other guarantees were negotiated.
>
>   Sticking to an ancient compiler defeats the eat your own 
> dogfood goal underlying the C++ -> D transition.

Realistically this isn't happening, since the compiler doesn't 
use the stdlib or gc anyway.

> The latest released frontend versions are at the moment:
> 2.078 - dmd (2.078.1)
> 2.077 - ldc (1.7.0)
> 2.068 - gdc (6.3.0+2.068.2)
>
> So technically we could only upgrade to 2.068 atm.
> Would be good to hear some release plans from the GDC team for 
> this year.
>
> ==========
>
> Just in case this is what dmd's schedule looks like for 2018.
>
> 2.078.0 - 2018-01-01
> 2.079.0 - 2018-03-01
> 2.080.0 - 2018-05-01
> 2.081.0 - 2018-07-01
> 2.082.0 - 2018-09-01
> 2.083.0 - 2018-11-01
> 2.084.0 - 2019-01-01
>
> I wished the semver discussion¹ would have been a bit more 
> decisive and we'd started out the year with 8.0.0 (majors every 
> 6 months, minors every 2 months). Hopefully we take the chance 
> of relabeling 2.080.0 to 8.0.0.
>
> [¹]: 
> http://forum.dlang.org/post/eghpfllbnvvlskbdpwfj@forum.dlang.org

I hope that happens, but 18.0 would be better, so it matches the 
year.