Any code in lib/ shouldn't have to care about doing this. 
Any required setup must be done in the GR C++ part

Do you mean in xxx_sink_c_impl, or are you thinking that GR would do it in it's initial GUI setup?  

 Also using a magic 'USING_GLEW' that must somehow be setup manually is  
not acceptable. Need some CMake logic to detect when this is required and automatically set it up.

Sure.  I don't disagree, but I'm not sure what other configurations would require Glew, so since I couldn't vouch for anything but Win10-64/MSVC, I left it as a manual option that can then be specified on the CMake command line (which is what my build scripts are doing now).  If you can point in to what configurations overall would need this, then happy to submit a new change.  

Geof


On Sat, Apr 23, 2016 at 9:28 PM, Sylvain Munaut <246tnt@gmail.com> wrote:
Hi,

Thanks for the patches. Comments below.


> 1- Allows compilation on MSVC by conditionally adding __attribute(format
> tags based on the compiler

I merged an equivalent patch, it'll be pushed whenever I push my next
series of update for fosphor.


> 2- Allows builders to use Glew when required, making a GlewInit call when
> USING_GLEW is defined. If that is not defined, there are no changes.

Any code in lib/ shouldn't have to care about doing this. It expects
that all the required GL setup has been done prior to calling it. Any
required setup must be done in the GR C++ part

Also using a magic 'USING_GLEW' that must somehow be setup manually is
not acceptable. Need some CMake logic to detect when this is required
and automatically set it up.


Cheers,

   Sylvain