Core/VMaps: Use fabs instead of abs for float type. On some platforms abs has only int overload exists.

src/server/collision/Models/WorldModel.cpp

@@ -42,7 +42,7 @@ namespace VMAP
         const Vector3 p(ray.direction().cross(e2));
         const float a = e1.dot(p);
 
-        if (abs(a) < EPS) {
+        if (fabs(a) < EPS) {
             // Determinant is ill-conditioned; abort early
             return false;
         }