Install wxrc with proper library dependencies under OS X.

Install wxrc with proper library dependencies under OS X.

In addition to changing the libraries themselves to point to the dependencies
in their installed location, we also need to do the same thing for wxrc when
installing it under OS X, otherwise it wouldn't run once the libraries are not
available in their original location any more.

Closes #15452.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74909 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775