virtual packages and X11 vs. X11R<specific_number>

[mitchell@mdd.comm.mot.com (Bill Mitchell)]

Ian Jackson <iwj10@cus.cam.ac.uk>

> X Windows:
> ----------
> X11R5                   XFree86 R5, including base system (obsolete)
> xR5shlib                XFree86 R5 shared library only
> X11R6                   XFree86 R6, including base system
> xR6shlib                XFree86 R6 shared library only
> xlibraries              XFree86 R6 shared library or stub library
> xserver                 Any X server (used by other X packages)

Would it make sense to further virtualize X11R5 and X11R6 and provide
a virtual X11 package for use as a dependency?  If we don't do this,
what happens when X11R7 is released?  Must all X11R6-dependent
packages be updated?

And, on a somewhat-related issue:

    /usr/include/X11 -> ../X11R6/include/X11
    /usr/bin/X11 -> ../X11R6/bin
    /usr/lib/X11 -> ../X11R6/lib/X11

However

    /usr/X11R6/lib doesn't appear to be the target of a symlink.

/usr/X11R6/lib contains X11 libraries needed at package build time.
How about something like

    /usr/X11/lib -> /usr/X11R6/lib

to allow decoupling library-search paths from X11R6 specificity for
developers and maintainers of X11 packages.