UNITED States President Bush has won the backing of the world's leading arms exporters - the five permanent members of the United Nations Security Council - for his plan to limit Middle East arms arsenals.At a two-day meeting that ended in Paris Tuesday, representatives of the US, the Soviet Union, China, Britain, and France gave a virtual point-by-point endorsement to an arms control plan Mr. Bush put forward in May. Delegates whose countries currently provide the vast majority of arms bought by the Middle East agreed on the need to rid the region of the weapons of mass destruction. They agreed countries in the area should sign a global treaty banning chemical weapons, stop importing materials usable in nuclear weapons and - in a point apparently aimed at Israel - allow nuclear activities to be inspected. There should be a freeze on ground-to-ground missiles, eventually leading to a total ban. The five also promised to draw up guidelines on how to restrain sales of conventional weapons to the region and improve communication on arms transfers.