bug#39883: 28.0.50; macOS blank frame

[Alan Third]

On Wed, Apr 01, 2020 at 09:51:37AM +0530, Ashish SHUKLA wrote:
> On 3/31/20 10:22 PM, Alan Third wrote:
> > On Mon, Mar 30, 2020 at 01:24:59AM +0530, Ashish SHUKLA wrote:
> >>
> >> It seems like building with same configure flags, but outside nix causes
> >> issue to disappear. So, maybe it's something to do with the nix 
> >> environment.
> > 
> > Nix used to use headers from macOS 10.10 or thereabouts, even on newer
> > versions of macOS. I don’t know if this is still the case. The problem
> > is that our compile‐time feature detection code detects the wrong
> > features as a result.
> > 
> > Could you perhaps try changing src/nsterm.h so that this:
> > 
> > #define NS_DRAW_TO_BUFFER 1
> > 
> > is always defined? You should be able to just delete or comment out
> > the #if and #endif.
> > 
> > I don’t know how easy that is for you with Nix, hopefully it’s pretty
> > straight forward.
> > 
> 
> Hi Alan,
> 
> It turns out after deleting those lines the problem is resolved. I will
> investigate on Nix side, what went wrong.

It’s quite possible we’ll need to provide some sort of option to force
this, or to do run‐time feature detection. I don’t much fancy trying
to code up the runtime detection for this feature, but if we need it
we need it.

For my own future reference: perhaps we should do a test in
./configure rather than rely on the contents of the headers?
-- 
Alan Third