[Mesa-dev] [PATCH v3 1/2] configure+mesa/st: unify check for -std=c++11 support and enable accordingly

[Gert Wollny]

Am Montag, den 02.10.2017, 15:16 +0100 schrieb Emil Velikov:
> 
> 
> While rebuilding most of Mesa + its tests (as illustrated in 2/2)
> only for a single test is very wasteful.
> 
> Let's not do that, pretty please?

I'm not quite sure what you mean by that. IHMO as long as mesa is
supposed to support pre c++11 compilers at least one build on travis
should account for this - especially considering that now, with g++ >=
6 enabling c++14 by default and being the compiler of choice in
Debian/stable and derivatives, there is a certain danger that c++11 or
even c++14 code creeps in without the authors and reviewers realizing
it (as [1] showed).

[1] https://bugs.freedesktop.org/show_bug.cgi?id=103002   
  (string_buffer_test.cpp:43: error:  ISO C++ forbids 
   initialization of member ‘str1’)

FWIW, personally I'd prefer if mesa would already require a c++11
capable compiler considering that with LLVM >= 3.9  the -std=c++11 flag
is already forced on all depending modules via LLVM_CXXFLAGS.

> 
> > [...]
> > 
> > > 
> 
> I'm roughly aware of the advantages, although I'm also thinking of
> the disadvantages. 
> Close to nobody is interested in reading or maintaining m4, that I
> know of. Thus having a custom one in tree is a bad idea.
Okay, the updated patch will use the AX_CHECK_COMPILE_FLAG.

Best, 
Gert