Add mju_euler2Quat.

PiperOrigin-RevId: 623469398
Change-Id: Ia86b29a764018cd4c3bc57d23616bed7393081f5

include/mujoco/mujoco.h

@@ -1033,7 +1033,6 @@ MJAPI void mju_transformSpatial(mjtNum res[6], const mjtNum vec[6], int flg_forc
                                 const mjtNum newpos[3], const mjtNum oldpos[3],
                                 const mjtNum rotnew2old[9]);
 
-
 //---------------------------------- Quaternions ---------------------------------------------------
 
 // Rotate vector by quaternion.
@@ -1072,6 +1071,9 @@ MJAPI void mju_quatIntegrate(mjtNum quat[4], const mjtNum vel[3], mjtNum scale);
 // Construct quaternion performing rotation from z-axis to given vector.
 MJAPI void mju_quatZ2Vec(mjtNum quat[4], const mjtNum vec[3]);
 
+// Convert sequence of Euler angles (radians) to quaternion.
+// seq[0,1,2] must be in 'xyzXYZ', lower/upper-case mean intrinsic/extrinsic rotations.
+MJAPI void mju_euler2Quat(mjtNum quat[4], const mjtNum euler[3], const char* seq);
 
 //---------------------------------- Poses ---------------------------------------------------------