(scm_to_short, scm_to_ushort): It's SHRT_MIN, etc, not SHORT_MIN.

(scm_to_short, scm_to_ushort): It's SHRT_MIN, etc, not SHORT_MIN.
(scm_to_size_t): Use SIZE_MAX instead of cooking our own.
(scm_to_long_long, scm_to_ulong_long, scm_to_int8, scm_to_uint8,
scm_to_int16, scm_to_uint16, scm_to_int32, scm_to_uint32,
scm_to_int64, scm_to_uint64, scm_to_intmax, scm_to_uintmax,
scm_from_long_long, scm_from_ulong_long, scm_from_int8,
scm_from_uint8, scm_from_int16, scm_from_uint16, scm_from_int32,
scm_from_uint32, scm_from_int64, scm_from_uint64, scm_from_intmax,
scm_from_uintmax): New.