You can write a view_check function yourself using vec_dot, planes and normals.

Assume you have the normal of a plane (read: one side of the view frustum) pointing outside, then check
d = vec_dot(pos,normal) - vec_dot(camera.x,normal);
for all bounding box vertices/ their positions "pos". If d is negative for one of them, repeat the same process with the other 3 relevant view frustum planes. If one of the d values is negative for all 4 planes, the entity's bounding box intersects the view frustum.