Bug#1102742: eureka: it looks like eureka could be rebuilt against fltk1.4

[Aaron M. Ucko]

Thanks for copying me!

Alexandre Detiste <alexandre.detiste at gmail.com> writes:

> eureka builds again fltk1.4 if I add this to d/rules:
>     +               -DCMAKE_CXX_FLAGS="-I/usr/include/cairo $(CXXFLAGS)" \
>
> I hoped this would be automatically handled in fltk1.4 somehow.
> I found no pkgconfig file to patch.

FLTK has never provided pkgconfig files, just CMake glue and a dedicated
fltk-config (which I've multiarchified).  I've double-checked that both
acknowledge the need for -I/usr/include/cairo, but for some reason
eureka doesn't pick that up despite using CMake. :-/

> Then it builds but segfault without displaying anything.

That's because it's not ready for Wayland -- it assumes in several
places that on platforms other than macOS and Windows, it will have a
non-NULL fl_display which it can supply to X11 APIs.  FLTK 1.4 offers a
mechanism such apps can use to make it stick with the X11 backend:

https://salsa.debian.org/ucko/fltk1.4/-/blob/main/README.Wayland.txt?ref_type=heads#L57

I've locally confirmed it works here.

-- 
Aaron M. Ucko, KB1CJC (amu at alum.mit.edu, ucko at debian.org)
http://www.mit.edu/~amu/ | http://stuff.mit.edu/cgi/finger/?amu@monk.mit.edu