[Buildroot] [PATCH] pinentry: fix build issue with gcc 5.x

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello,

On Sat, 20 Aug 2016 13:19:02 -0700, Khem Raj wrote:

> > +# pinentry uses some std::string functionality that needs C++11
> > +# support when gcc >= 5.x. This should be removed when bumping
> > +# pinentry, since newer versions no longer use std::string.
> > +ifeq ($(BR2_TOOLCHAIN_GCC_AT_LEAST_5),y)
> > +PINENTRY_CONF_ENV = CXXFLAGS="$(TARGET_CXXFLAGS) -std=gnu++11"
> > +endif  
> 
> Should this package be restricted to gcc5 and newer only, I assume
> it will break with gcc 4.x too and c++11 may not be there, gcc5 atleast
> has the support its just not default

We have lots of gcc 4.x toolchains, and we haven't had any build
failure. I believe it builds fine with gcc 4.x.

The code requiring C++11 that causes the build failure with gcc 5.x is
in libstdc++ itself. As I discussed with Yann on IRC, I don't really
understand why some code in libstdc++ uses C++11, without gcc 5.x
defaulting to C++11.

Maybe you have a clue?

Thanks,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com