/** @def WCSTRIG_TOL
* @brief Domain tolerance for asin() and acos() functions.
*
* Domain tolerance for the asin() and acos() functions to allow for floating
* point rounding errors.
*
* If @f$v@f$ lies in the range @f$1 < |v| < 1 + WCSTRIG\_TOL@f$ then it will
* be treated as @f$|v| == 1@f$.
*/
