(gud-running): Rename from gdb-running. Update uses.

(gud-running): Rename from gdb-running.  Update uses.
(gud-tool-bar-map): Use tool-bar-local-item-from-menu rather than
tool-bar-add-item-from-menu to avoid let binding tool-bar-map
which fails if tool-bar.el is loaded in the mean time.
(gud-file-name): New fun.
(gud-find-file): Use it as default value for gud-find-file.
(gud-speedbar-buttons): Discriminate on gud-minor-mode rather than
on gud-find-file.
(gud-gdb-find-file, gud-dbx-file-name, gud-dbx-find-file)
(gud-xdb-file-name, gud-xdb-find-file, gud-perldb-find-file)
(gud-pdb-find-file, gud-jdb-find-file): Remove.
(gud-query-cmdline): Don't stuff the whole cwd in the command.
(gdb, dbx, xdb, perldb, pdb, jdb): Use the default for gud-find-file.
(gud-mipsdbx-massage-args): Remove.
(gud-dbx-command-name): New var.  Do what gud-mipsdbx-massage-args did.
(gud-irixdbx-marker-filter): Use match-string and gud-file-name.
(gud-jdb-command-name): New var.
(gud-common-init): Re-instate RMS code of 11/13.