Disable use of LIBDECOR on WAYFIRE as it causes Blender to hang
on window creation.
Detect WAYFIRE using the presence of the `zwf_shell_manager_v*`
interface, don't use LIBDECOR if this is found.
This is an alternative fix to [0] which also disabled LIBDECOR
but caused LIBDECOR not to be used in GNOME on some systems.
I'm not keen on this solution, but it seems alternatives are less
reliable. See code-comment for details.
[0]: 3a5389d5ab
e8de8ee85a