cmake: get_whole_archive_options macro -> function

cmake/WholeArchive.cmake

@@ -1,10 +1,10 @@
-macro (get_whole_archive_options OUT_VAR)
+function (get_whole_archive_options OUT_VAR)
     # We use --whole-archive because OSG plugins use registration.
     if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-        set(${OUT_VAR} -Wl,--whole-archive ${ARGN} -Wl,--no-whole-archive)
+        set(${OUT_VAR} -Wl,--whole-archive ${ARGN} -Wl,--no-whole-archive PARENT_SCOPE)
     elseif (CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
-        set(${OUT_VAR} -Wl,-all_load ${ARGN} -Wl,-noall_load)
+        set(${OUT_VAR} -Wl,-all_load ${ARGN} -Wl,-noall_load PARENT_SCOPE)
     else ()
         message(FATAL_ERROR "get_whole_archive_options not implemented for CMAKE_CXX_COMPILER_ID ${CMAKE_CXX_COMPILER_ID}")
     endif()
-endmacro (whole_archive_options)
+endfunction (whole_archive_options)