[Ada] User Guide?

[dewar@gnat.com]

<<The files checked into CVS should process in Texinfo without any special
magic or additional preprocessing, so they can go in onlinedocs.  It's OK
if this gives a Unix-style manual and the VMS one is given by using
-DVMSSTYLE to texi2dvi/makeinfo/....
>>

I think this should be achievable with the approach we have in mind for
the users guide. We will take care of the minor issues for gnat_rm.texi.