Add additional math constants

Add math constants which are defined in libc math.h but not ours.
Keep constants in rs_types.rsh instead of rs_math.rsh to avoid
problems with including rs_math.rsh in other projects (namely
libbcc).

Change-Id: I7c48a4c3585739a2f16f3da91aad67271975d1e1
1 file changed