Use old syntax for CMake's separate_arguments() to restore compatiblity with old CMake versions.
Reference issue
This should fix #2866 (closed) however I can't test this myself since I don't have access to a Mac. @barracuda156 can you verify that this patch resolves the issue?
What does this implement/fix?
This patch changes a call to separate_arguments() added in bc424f61 to use the old syntax.