[build2] Same assertion failure on macOS (clang++) and Debian linux (g++)

[Boris Kolpackov]

Chase Metzger <chasemetzger15 at gmail.com> writes:

> libmhello-1.0.0/build/root.build:13:1: error: assertion failed: c++
>   compiler does not support modules

Compiler support for Modules TS is still very patchy so in build2 we
only enable it for very recent versions (see cxx/init.cxx for details).
But you can force it:

cxx.std = experimental
cxx.features.modules = true


> I get this message both on macOS 10.13.4 with this as the clang++ --version
> output:
> 
> Apple LLVM version 9.1.0 (clang-902.0.39.1)

For Clang I would suggest using the latest version your can get your
hands on (6.0.0 or better yet trunk). Even then, expect fireworks.


> And on Debian 9 stretch with this as the g++ --version output:
> 
> gcc version 6.3.0 20170516 (Debian 6.3.0-18)

For GCC you will need to use the c++-modules branch:

https://gcc.gnu.org/wiki/cxx-modules

Also, I wouldn't expect it to be able to handle libstd-modules yet.

Currently, your best chance of having something even remotely usable
is probable VC (version 15.6 or higher).

Boris