[Buildroot] [PATCH v2, 1/1] package/wireshark: fix static build with snappy

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

On Tue, 28 May 2019 23:04:28 +0200
Arnout Vandecappelle <arnout@mind.be> wrote:

> >> Is this really the right thing to do? Ideally a program written in C
> >> should not have to know that a library it is using is written in C++.  
> 
>  Hm, good point... Snappy provides a C wrapper, so there should indeed not be a
> need for the client to use the C++ linker. Of course, there also shouldn't be a
> need for the client to link with libstdc++ :-).

There is no need to link with libstdc++ when dynamic linking is used,
which to me is another indication that using the C++ linker is not the
right approach. Adding -lstdc++ is only necessary in static linking
configuration, for the usual reason that libA -> libB -> libC in static
linking scenarios requires passing -lC when linking libA.

> >> and there's a few other examples in the tree. To be honest, I don't
> >> know what is the most correct solution, I'm just trying to make
> >> sure we solve a given problem in the same way everywhere.  
> 
>  In most other cases we don't do any patching but we pass it through
> LIBS or similar. I don't think that that's possible with CMake.
> 
>  For ICU, we patch the .pc file, which is the proper thing to do, but
> Snappy doesn't have a .pc file.

Yes, but to me that's another indication that the right thing to do is
to pass -lstdc++: if the packages were better, they would be using .pc
files, and we would be able to specify -lstdc++ in their Libs.private.
Once again, it shows that using the C++ linker is (to me) not the right
approach.

> > I don't know either. You can apply the first or the second version
> > of this patch.  
> 
>  I reset its state to New. Now Thomas can decide :-)

For the reasons stated above, I think I prefer v1.

>  Maybe just send both versions upstream, since you have them both
> now. Then they can choose which one they like better.

The most correct solution for upstream would be for snappy to provide
a .pc file, and for wireshark to use it.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com