The build_local_string macro was used in two ways: (1) string literals for which scoped allocation suffices, and (2) file name components, where it's not safe in general to assume bounded-size ASCII data. Simplify by defining a new macro SCOPED_STRING that allocates a block-scope string, and by using SCOPED_STRING for (1) and build_string for (2). Furthermore, actually use stack allocation only for objects known to have sufficient alignment. This simpler implementation means Emacs can make USE_STACK_LISP_OBJECTS the default unless GC_MARK_STACK != GC_MAKE_GCPROS_NOOPS. * lisp.h (GCALIGNED): Align even if !USE_STACK_LISP_OBJECTS, for fewer differences among implementations. (struct Lisp_String): Now GCALIGNED. (USE_STACK_LISP_OBJECTS): Default to true, since the implementation no longer insists on a nonempty GCALIGNED. But make it false if GC_MARK_STACK != GC_MAKE_GCPROS_NOOPS. (SCOPED_CONS_INITIALIZER): Remove, since it's no longer needed separately. Move definiens to scoped_cons. The old definition was incorrect when GCALIGNED was defined to be empty. (union Aligned_String): New type. (USE_STACK_CONS, USE_STACK_STRING): New constants, so that the implementation ports to compilers that don't align strictly enough. Don't worry about the union sizes; it's not worth bothering about. (scoped_cons, scoped_list1, scoped_list3, scoped_list4): Rewrite using USE_STACK_CONS. (scoped_cons): Assume the use of union Aligned_Cons. (lisp_string_size, make_local_string, build_local_string): Remove. Unless otherwise specified, all callers of build_local_string changed to use SCOPED_STRING. (SCOPED_STRING): New macro. * data.c (wrong_choice): * menu.c (single_menu_item): * process.c (Fformat_network_address): Hoist use of SCOPED_STRING out of a scope, so that its returned object lives long enough. * fileio.c (Fexpand_file_name): Use build_string, not SCOPED_STRING, as the string might be long or might not be ASCII.