.Sanitize: reflect removal of gdb-all.texi from repository

.Sanitize: reflect removal of gdb-all.texi from repository

lucid.m4: config for Lucid/NCR (like "all.m4" but also turns on _LUCID__)

none.m4: turn _LUCID__ off by default

gdb.texinfo:
1) Use bold rather than italic for user input in intro, to avoid discord
   with meta-variable convention throughout manual (jim@wrs.com suggestion).
2) Some mumbling about using GDB under Energize/Cadillac.
   (conditionalized on _LUCID__, not included yet in general-doc config)
3) more remarks about debugging optimized code, incl vanishing unused vars
   (rms/gnu/net suggestion).
4) @emph replaces @i in a few spots (emphasis should affect info file as
   well as printed manual).
5) "memory tracing", "breakpoint on variable modification" index entries
   added, pointing to watchpoints (gnu suggestion).
6) Less passive, more index entries, in breakpoint-number description
7) doc new convenience var $bpnum (due to grossman?)
8) Update "info breakpoints" to describe new Grossman format; note now
   synonymous with "info watchpoints".
9) Describe negative (GDB internal) breakpoints and new "info all-breakpoints"
10) Slight change to description of colon-colon GDB expression notation,
   describing function::var as well as file::var and noting var is static
   (lmb question, gnu suggestion)
11) Doc Per's new &(&foo) for debugging C++
12) Rephrase paragraph in configure appendix to avoid overfull box
    (in *large* format!)
13) Additional warning re VPATH feature required for --srcdir= config.
    (gnu suggestion)