There are a few cases in FreeBSD where the expression (1 << 31) is used.
However this produces undefined behavior as '1' is of type int. (see
6.4.4p5: The type of an unmarked integer constant is the first of the
following list in which its value can be represented: int, long int,
long long int). The shift of 31 is illegal (see 6.5.7p4) if the size
of an int is 32.