Probably because of this:
-- Found PythonInterp: /usr/bin/python (found version "3.5.2")
[100%] Generating conftypes.py
File "./gentypes.py", line 24
print "# content generated by %s" % os.path.basename(sys.argv[0])
^
SyntaxError: invalid syntax
make[2]: *** [python-ui/CMakeFiles/conftypes.dir/build.make:62: python-ui/conftypes.py] Error 1
make[2]: *** Deleting file 'python-ui/conftypes.py'
make[1]: *** [CMakeFiles/Makefile2:1038: python-ui/CMakeFiles/conftypes.dir/all] Error 2
make: *** [Makefile:128: all] Error 2
I guess python-ui/gentypes.py expects python2.