* Makefile.in (DEMANGLING_STYLE): New define to set default

	* Makefile.in (DEMANGLING_STYLE):  New define to set default
	demangling style for C++.  Defaults to "auto".
	* Makefile.in (DEMANGLE_OPTS):  Use DEMANGLING_STYLE.
	* Makefile.in (SFILES_MAINDIR):  Add demangle.c
	* Makefile.in (OBS):  Add demangle.o
	* cplus-dem.c (GNU_DEMANGLING, ARM_DEMANGLING, LUCID_DEMANGLING):
	Remove compile time decisions about demangling style and replace
	with runtime decisions using current_demangling_style.
	* cplus-dem.c (main):  Expand code included during building of
	standalone demangler to recognize demangling style options.
	* dbxread.c (demangle.h):  Include.
	* dbxread.c (read_ofile_symtab, process_one_symbol):  Set GNU C++
	demangling style if processing g++ code and current demangling style
	is auto (Note: this feature currently disabled.)
	* demangle.c:  New file, generic demangling control.
	* demangle.h (demangling_styles):  New enumeration to select one
	of several demangling styles.  Also define string names for each
	style.
	* demangle.h (set_demangling_style):  Add prototype.
	* dwarfread.c (demangle.h):  Include.
	* dwarfread.c (GPLUS_PRODUCER, LCC_PRODUCER, CFRONT_PRODUCER):
	New producer string prefixes to recognize.
	* dwarfread.c (handle_producer):  Consolidate actions for specific
	producers.  Set demangling style based on producer string if
	current style is auto.  (Note: this feature currently disabled.)
	* config/ncr3000.mt (DEMANGLE_OPTS):  Remove.