Fix MACOSX_RPATH (again)

Disappeared in the last merge request.
Did `git reset --soft upstream/release/1.Y` without first update branch

Author: arnfinn

src/CMakeLists.txt

@@ -31,6 +31,7 @@ if(NOT STATIC_LIBRARY_ONLY)
     set_target_properties(pcm-shared PROPERTIES SOVERSION ${PROJECT_VERSION_MAJOR}
                                                 CXX_VISIBILITY_PRESET hidden
                                                 VISIBILITY_INLINES_HIDDEN 1
+                                                MACOSX_RPATH ON
                                                 OUTPUT_NAME "pcm"
                                                 EXPORT_NAME "pcm")