Declare base NSAccessibility functions and constants, which have been
implemented as stubs.
In the near future, we could begin supporting some NSAccessibility
informal protocol features (for instance, elements ignored in the
accessible view hierarchy). However, for even considering thorough
accessibility support we would require, at least:
* A proper implementation of the AX* API in gnustep-boron;
* Design integration with screen reading software and other components
for an accessible graphic environment.
which are most certainly long-term tasks.
