fix some abs() type conversion warnings

code/math/ik_solver.cpp

@@ -204,7 +204,7 @@ bool ik_constraint_window::constrain(matrix& localRot, bool /*backwardsPass*/) c
 	
 	//Clamp absolute value of individual angles to window
 	for (float angles::* i : pbh) {
-		const float absAngle = abs(currentAngles.*i);
+		const float absAngle = std::abs(currentAngles.*i);
 		if(absAngle > absLimit.*i){
 			needsClamp = true;
 			currentAngles.*i = copysignf(std::min(absAngle, absLimit.*i), currentAngles.*i);

code/model/modelread.cpp

@@ -1065,7 +1065,7 @@ float get_submodel_delta_angle(const submodel_instance *smi)
 float get_submodel_delta_shift(const submodel_instance *smi)
 {
 	// this is a bit simpler
-	return abs(smi->cur_offset - smi->prev_offset);
+	return std::abs(smi->cur_offset - smi->prev_offset);
 }
 
 void do_new_subsystem( int n_subsystems, model_subsystem *slist, int subobj_num, float rad, const vec3d *pnt, char *props, const char *subobj_name, int model_num )
@@ -4388,7 +4388,7 @@ void submodel_look_at(polymodel *pm, polymodel_instance *pmi, int submodel_num)
 
 	// calculate turn rate
 	// (try to avoid a one-frame dramatic spike in the turn rate if the angle passes 0.0 or PI2)
-	if (abs(smi->cur_angle - smi->prev_angle) < PI)
+	if (std::abs(smi->cur_angle - smi->prev_angle) < PI)
 		smi->current_turn_rate = smi->desired_turn_rate = (smi->cur_angle - smi->prev_angle) / flFrametime;
 
 	// and now set the other submodel fields

code/physics/physics.cpp

@@ -1249,7 +1249,7 @@ bool physics_lead_ballistic_trajectory(const vec3d* start, const vec3d* end_pos,
 
 		time = range / (weapon_speed * cosf(angle));
 
-		if (abs(time - best_guess_time) < 0.01f)
+		if (std::abs(time - best_guess_time) < 0.01f)
 			break;
 		else
 			best_guess_time = time;