x11/py-tk situation on macos

[clément bouvier <clement.bouvier.europe%gmail.com@localhost>]

Hi all,

x11/py-Tk does not build on macos, but the problem might be more on x11/tk…

Initially x11/py-Tk had an explicit dependency on libx11 [1], corrected later [2] and finally removed [3].
The dependency of X11 or not is related to x11/tk headers.
x11/tk main header, tk.h, includes x11/xlib:

#ifndef _XLIB_H
#   include <X11/Xlib.h>
#   ifdef MAC_OSX_TK
#       include <X11/X.h>
#   endif
#endif

The big problem is that Tk has on macos two backends:
- x11 oriented,
- quartz oriented (named "aqua" by Tk, macOS specific).
Whatever the backend you choose at compile time, tk.h includes X11 headers:
 - In the x11 backend, Xlib.h is a reference to an external implementation of xlib;
-  In the "quartz" backend, Xlib.h is a reference to a local header coming with Tk.
If you compile Tk with X11 backend on macos, py-Tk will should have a X11 dependency.
On the contrary, if compiled with "quartz" backend, py-Tk should not have a X11 dependency but Tk puts its "X11" local headers directly under X11 directory and tk.h cannot easily include Xlib local header.
Consequently, we have a name collision if we have some X11 related stuff on macos and we want to have Tk built with quartz backend.
The behaviour is known because we have a comment in the Makefile of x11/tk:

# IMPORTANT: This option should be enabled on a system without X11.
# Otherwise some X11 headers are installed and will break X11 compatibility.

Now the problem is that for x11/py-Tk, the dependency depends on tk backend.
If by default we build Tk with X11 backend, then we should have an X11 dependency for x11/py-Tk.

I have already submitted a patch upstream concerning the name collision with X11 headers because it affects all downstream (macports have patches to avoid the name collision typically) but upstream does not seem very reactive…[4] 

Note python proposes as installer Tkinter with Tk "quartz" backend on macos...

Does someone have ideas to unbreak x11/py-tk?

[1] http://cvsweb.netbsd.org/bsdweb.cgi/pkgsrc/x11/py-Tk/Makefile.diff?r1=1.61&r2=1.62&f=h
[2] http://cvsweb.netbsd.org/bsdweb.cgi/pkgsrc/x11/py-Tk/Makefile.diff?r1=1.63&r2=1.64&f=h
[3] http://cvsweb.netbsd.org/bsdweb.cgi/pkgsrc/x11/py-Tk/Makefile.diff?r1=1.65&r2=1.66&f=h
[4] https://core.tcl-lang.org/tk/tktview?name=17f427c728

Clément.