Following the kbproto convention, the headers will be named XKBcommon.h
and XKBcommonint.h. Furthermore, they'll be installed in X11/extensions
directory with the rest of the XKB headers.
A test program and script have been added for checking the XkbCommon
keysym functions. This has already highlighted an error in handling of
keysyms from XF86keysym.h.