Fix rpath on macOS

Author: redsun82

patches/swift/04-allow-plugging-in-observer.patch

@@ -1,12 +1,12 @@
 diff --git a/cmake/modules/AddSwift.cmake b/cmake/modules/AddSwift.cmake
-index 6d93e52f1d5..9ab79aeb9d6 100644
+index 6d93e52f1d5..c4fe5b760a8 100644
 --- a/cmake/modules/AddSwift.cmake
 +++ b/cmake/modules/AddSwift.cmake
 @@ -715,6 +715,7 @@ function(add_swift_host_tool executable)
 
          # Include the abi stable system stdlib in our rpath.
          list(APPEND RPATH_LIST "/usr/lib/swift")
-+        list(APPEND RPATH_LIST "${SWIFTLIB_DIR}")
++        list(APPEND RPATH_LIST "@executable_path/../lib")
 
        elseif(BOOTSTRAPPING_MODE STREQUAL "CROSSCOMPILE-WITH-HOSTLIBS")