Properly handle rpath on macOS
Without this, the install_name of JAlienROOT is libJAlienROOT rather than @rpath/libJAlienROOT, with the result things might break when SIP is enabled.
Without this, the install_name of JAlienROOT is libJAlienROOT rather than @rpath/libJAlienROOT, with the result things might break when SIP is enabled.