PR c++/11990:

	PR c++/11990:
	* c-lang.c (cplus_language_defn): Use gdb_demangle.
	* c-typeprint.c (c_type_print_base): Use gdb_demangle.
	* cp-support.c (mangled_name_to_comp): Use gdb_demangle.
	(gdb_demangle): New function.
	* cp-support.h (gdb_demangle): Declare.
	* dwarf2read.c (dwarf2_physname, fixup_partial_die)
	(dwarf2_name): Use gdb_demangle.
	* gdbtypes.c (check_stub_method): Use gdb_demangle.
	* gnu-v3-abi.c (gnuv3_rtti_type): Strip @plt and version
	suffixes from name.
	(gnuv3_print_method_ptr): Use gdb_demangle.
	* jv-lang.c (java_demangle): Use gdb_demangle.
	* jv-typeprint.c (java_type_print_base): Use gdb_demangle.
	* language.c (unk_lang_demangle): Use gdb_demangle.
	* symtab.c (symbol_find_demangled_name)
	(demangle_for_lookup): Use gdb_demangle.