of the typedefs off_t and pid_t when use of the latter would cause
namespace pollution. These macros are used like _BSD_VA_LIST_ and
aren't #undef'ed when the corresponding typedef is declared.
off_t is very machine-dependent and should never have been decided
in <sys/types.h> (its declaration is compiler-dependent). pid_t
isn't very machine-dependent, but this might change. `long' is
a wasteful type for it if longs are longer than ints.
Move the definition of _BSD_VA_LIST_ away from the comment that
suggests that it is #undefed when va_list is declared.