(__xstrtol, __strtol, __unsigned): Remove macro decls. <inttypes.h>: Include if HAVE_INTTYPES_H. (_DECLARE_XSTRTOL): New macro. (xstrtol, xstrtoul, xstrtoumax): Declare all three functions, so that we need only one include file, not three. (_STRTOL_ERROR): Do not undef, as this is no longer needed. Reword overflow message so that it's independent of type.