Here you go!

Code:
#include <acknex.h>
#define PRAGMA_PATH "%EXE_DIR%\\templates\\models"

void ent_rotateXY_from_point ( ENTITY *ent, VECTOR *vRotOrigin, var angRotation )
{
	VECTOR vTemp;
	vec_diff ( vTemp, ent.x, vRotOrigin );
	vec_rotate ( vTemp, vector ( angRotation, 0, 0 ) );
	vec_add ( vTemp, vRotOrigin );
	vec_set ( ent.x, vTemp );
	ent.pan += angRotation;
}

void main ()
{
	level_load ( "" );
	camera.x = -500;
	camera.z = 200;
	camera.tilt = -20;
	ENTITY *ent = ent_create ( "buggy.mdl", nullvector, NULL );
	while ( !key_esc )
	{
		ent_rotateXY_from_point ( ent, ent.max_x, time_step * 5 );
		wait(1);
	}
	sys_exit(NULL);
}



Salud!