add cmake rpath specification

Author: phlptp

CMakeLists.txt

@@ -267,12 +267,30 @@ if(NOT UNITS_HEADER_ONLY AND UNITS_BUILD_PYTHON_LIBRARY)
     # Install directive for scikit-build-core
     install(TARGETS units_llnl_ext LIBRARY DESTINATION units_llnl)
     if(UNITS_BUILD_SHARED_LIBRARY)
-        if(NOT MSVC)
-            target_link_options(units_llnl_ext PRIVATE "-Wl,-rpath='$ORIGIN'")
-            set_target_properties(
-                units_llnl_ext PROPERTIES INSTALL_RPATH_USE_LINK_PATH TRUE
-            )
-        endif()
+        
+
+# -------------------------------------------------------------
+# setting the RPATH
+# -------------------------------------------------------------
+if(NOT DEFINED CMAKE_MACOSX_RPATH)
+set(CMAKE_MACOSX_RPATH ON)
+endif()
+
+# add the automatically determined parts of the RPATH which point to directories outside the build
+# tree to the install RPATH
+if(NOT DEFINED CMAKE_INSTALL_RPATH_USE_LINK_PATH)
+set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
+endif()
+
+# Add the local directory to the rpath
+if(NOT APPLE)
+list(APPEND CMAKE_INSTALL_RPATH $ORIGIN)
+else()
+list(APPEND CMAKE_INSTALL_RPATH "@loader_path")
+list(APPEND CMAKE_INSTALL_RPATH "@executable_path")
+endif()
+
+
         install(
             TARGETS units
             RUNTIME DESTINATION units_llnl