Someone enquired in the general forum about bootstrapping the last C++ version of dmd for OpenBSD, so I tried it myself on linux/x64.  Unfortunately, both the origin/2.067 branch and v2.067.1 tag of dmd no longer build with the latest gcc 7.1.1 and clang 4.0.1:

g++ -m64 -c -Wno-deprecated -Wstrict-aliasing -fno-exceptions -fno-rtti -D__pascal= -DMARS=1 -DTARGET_LINUX=1 -DDM_TARGET_CPU_X86=1 -DDMDV2=1  -O2 -DDMDV2=1 -Iroot -MMD -MF port.deps root/port.c                                              In file included from root/port.c:587:0:                                        /usr/include/bits/mathdef.h:19:3: error: #error "Never use <bits/mathdef.h> directly; include <complex.h> instead"                                               # error "Never use <bits/mathdef.h> directly; include <complex.h> instead"        ^~~~~

OK, I know that one, I removed it from ldc sometime back:

https://github.com/ldc-developers/ldc/pull/1447#r60186297

Just remove that linux ifdef and its contents and I get to the backend:

g++ -m64 -c -Wno-deprecated -Wstrict-aliasing -fno-exceptions -fno-rtti -D__pascal= -DMARS=1 -DTARGET_LINUX=1 -DDM_TARGET_CPU_X86=1 -DDMDV2=1  -O2 -DDMDV2=1 -Iroot -Itk -Ibackend -I. -MMD -MF gdag.deps backend/gdag.c                        backend/go.c: In function 'int go_flag(char*)':                                 backend/go.c:82:5: error: narrowing conversion of '-1' from 'int' to 'mftype {aka unsigned int}' inside { } [-Wnarrowing]                                            };                                                                              ^

It appears that nobody is building the last C++ version of dmd and keeping it up to date, which is needed for porting to new platforms. Ldc has a ltsmaster branch, which uses dmdfe 2.068.2 with idgen.d reverted to idgen.c, that's kept up to date and integrated with CI:

https://github.com/ldc-developers/ldc/commits/ltsmaster

Perhaps dmd needs to do the same?  Ian talked of adding a dmd-cxx branch sometime back, looks like dmd needs one:

http://forum.dlang.org/thread/CABOHX+ckJbL1yGyZBz-Lqq1kVWX=XDy50CT_H9=BNvuquP_Mmg@mail.gmail.com

Otherwise, we'll have to tell all porters to use ldc ltsmaster instead, which could be a viable alternative too, since it supports a lot more platforms than dmd.

On 2017-07-17 17:56, Joakim via Dlang-internal wrote:
> Perhaps dmd needs to do the same?  Ian talked of adding a dmd-cxx
> branch sometime back, looks like dmd needs one:

Thanks for bringing this up. As everyone was in favor of dmd-cxx, but no one created it, I made the first step and branched dmd-cxx from v2.067.0:

https://github.com/dlang/dmd/tree/dmd-cxx
https://github.com/dlang/druntime/tree/dmd-cxx
https://github.com/dlang/phobos/tree/dmd-cxx

I don't know about the CIs though, probably all of them are going to fail because of the missing config files.
However, at least Travis and CircleCi since a few versions checkout the corresponding branch at the other repositories.
Not sure whether auto-tester does the same.

In any case, PRs to improve/fix dmd-cxx are welcome ;-)

On Monday, 17 July 2017 at 19:30:29 UTC, Sebastian Wilzbach wrote:
> On 2017-07-17 17:56, Joakim via Dlang-internal wrote:
>> Perhaps dmd needs to do the same?  Ian talked of adding a dmd-cxx
>> branch sometime back, looks like dmd needs one:
>
> Thanks for bringing this up. As everyone was in favor of dmd-cxx, but no one created it, I made the first step and branched dmd-cxx from v2.067.0:

Thanks, but could you do what Iain asked for in the thread I linked and base it off the v2.068.2 tag instead?

> In any case, PRs to improve/fix dmd-cxx are welcome ;-)

I'll at least get it building again, up to Iain to merge all the other changes he wants.

On 2017-07-19 18:39, Joakim via Dlang-internal wrote:
> On Monday, 17 July 2017 at 19:30:29 UTC, Sebastian Wilzbach wrote:
>> On 2017-07-17 17:56, Joakim via Dlang-internal wrote:
>>> Perhaps dmd needs to do the same?  Ian talked of adding a dmd-cxx
>>> branch sometime back, looks like dmd needs one:
>> 
>> Thanks for bringing this up. As everyone was in favor of dmd-cxx, but no one created it, I made the first step and branched dmd-cxx from v2.067.0:
> 
> Thanks, but could you do what Iain asked for in the thread I linked
> and base it off the v2.068.2 tag instead?

Oh I didn't see that. Done.
I also enabled branch protection for this branch, s.t. no one can accidentally force-push to this branch.

>> In any case, PRs to improve/fix dmd-cxx are welcome ;-)
> 
> I'll at least get it building again, up to Iain to merge all the other
> changes he wants.

Cool! As mentioned I don't know whether the auto-tester will work directly, or Brads needs to set up a new branch.