[PATCH v2] ci: check C++ headers with clang

[Aaron Conole]

David Marchand <david.marchand at redhat.com> writes:

> If not passing an explicit compiler for C++, meson uses c++ which
> defaults to /usr/bin/g++ on a Ubuntu system.
> Explicitly choose which compiler to use for C++.
>
> Signed-off-by: David Marchand <david.marchand at redhat.com>
> ---
> Changes since v1:
> - rebased,
> - moved CXX tweaking in the branch enabling headers check,
>

Not sure why we got a segfault with this in IOL:

 36/120 DPDK:fast-tests / eal_flags_misc_autotest        FAIL             3.78s   killed by signal 11 SIGSEGV

I don't think it is related.

Acked-by: Aaron Conole <aconole at redhat.com>