Allows selection of C++ demangler to be a configuration option
until multiple demanglers are supported.
* demangle.h: New include file for extended demangler support.
* breakpoint.c, gdbtypes.c, printcmd.c, stack.c, symtab.c,
utils.c, valprint.c: Include "demangle.h" and change all calls
to cplus_demangle() or fputs_demangled() to use individual
demangling options.
* valprint.c (type_print_1): Change options to cplus_demangle
to print demangled function args. Still broken, but now less so.
* cplus-dem.c: Include demangle.h, reorganize and update some
comments to reflect reality.
* cplus-dem.c (cplus_demangle, cplus_mangle_opname): Change
second arg from fixed integer to bit based multiple options.
* cplus-dem.c (optable): Reformat and replace ansi members with
bit based options.
* cplus-dem.c (do_type): Fix bug with parsing missing return type.
