pkg/50419: math/cantor fails to build with python34

[oster%netbsd.org@localhost]

	Note: There was a bad value `mediumk' for the field `Priority'.
	It was set to the default value of `medium'.

>Number:         50419
>Category:       pkg
>Synopsis:       math/cantor fails to build with python34
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Nov 10 17:40:00 +0000 2015
>Originator:     Greg Oster
>Release:        NetBSD 7.0
>Organization:
>Environment:
	
	
System: NetBSD mickey 7.0 NetBSD 7.0 (QUAD) #0: Mon Sep 28 11:54:36 CST 2015 oster@quad:/u1/builds/build265/src/obj/amd64/u1/builds/build265/src/sys/arch/amd64/compile/QUAD amd64
Architecture: x86_64
Machine: amd64
>Description:

The math/cantor package fails to build if python34 is the default python.
The error is as follows:

In file included from /usr/pkgsrc/math/cantor/work.mickey/.buildlink/include/python3.4/pytime.h:6:0,
                 from /usr/pkgsrc/math/cantor/work.mickey/.buildlink/include/python3.4/Python.h:65,
                 from /usr/pkgsrc/math/cantor/work.mickey/cantor-4.14.3/src/backends/python2/python2session.h:28,
                 from /usr/pkgsrc/math/cantor/work.mickey/cantor-4.14.3/src/backends/python2/python2completionobject.cpp:25:
/usr/pkgsrc/math/cantor/work.mickey/.buildlink/include/python3.4/object.h:435:23: error: expected unqualified-id before ';' token
     PyType_Slot *slots; /* terminated by slot==0. */
                       ^

The issue appears to be that 'slots' is a reserved keyword in Qt, and
causes conflicts:

 http://comments.gmane.org/gmane.comp.kde.releases/7327
 https://forum.qt.io/topic/30966/solved-qt-c-app-and-embedded-python/3
 http://stackoverflow.com/questions/23068700/embedding-python3-in-qt-5
 http://doc.qt.io/qt-4.8/signalsandslots.html#using-qt-with-3rd-party-signals-and-slots

>How-To-Repeat:

	set 'PYTHON_VERSION_DEFAULT = 34' in /etc/mk.conf
	cd /usr/pkgsrc/math/cantor
	make install
        
>Fix:

As a workaround(fix?), adding the following:

PYTHON_VERSIONS_INCOMPATIBLE=   33 34 

to math/cantor/Makefile
forces the build to use python27, which works fine.



>Unformatted: