This ensures all event listeners are removed before the emitting
wlroots object is being destroyed. This will be enforced with asserts
in wlroots 0.19 but there is no reason to not do it right now either.
This change in wlroots 0.19 is implemented via commit
8f56f7ca43257cc05c7c4eb57a0f541e05cf9a79
"Assert (almost all) signals have no attached listeners on destroy"
Made all header files to have LABWC_ prefix in include guard identifers.
Converted from __LABWC_ in 35 include/ files.
Converted from __LAB_ in 5 include/ files.
Added LABWC prefix to 3 include/ files.
Added include guards to 3 include/ files.
The double underscores were removed since according to C standard
those "are always reserved for any use".
