Prepare gdb for 64-bit obstacks

Prepare gdb for 64-bit obstacks

	* charset.c (convert_between_encodings): Cast result of obstack_base.
	* cp-valprint.c (cp_print_value_fields): Use size_t locals.
	* hppa-tdep.c (internalize_unwinds): Change "size" parm to size_t.
	(read_unwind_info): Use size_t for some locals.
	* jit.c (finalize_symtab): Likewise.
	* utils.c (hashtab_obstack_allocate): Likewise.
	* symmisc.c (print_objfile_statistics): Update format strings.