* libc/include/sys/types.h: Use __dev_t, __uid_t, and __gid_t to
typedef dev_t, gid_t, and uid_t.
* libc/include/sys/_types.h: Move previous dev_t, uid_t and gid_t
types.h code to here, but typedef __dev_t, __uid_t, and __gid_t instead.
Change to lower case for all __foo_t_defined names.
* libc/machine/spu/machine/_types.h: Add SPU specific __dev_t,
__uid_t, and __gid_t making them all four bytes. Change to lower case
for all __foo_t_defined names.