Make `os2` Linux `_is_path_separator` compare against `_Path_Separator`

core/os/os2/path_linux.odin

@@ -14,7 +14,7 @@ _Path_List_Separator   :: ':'
 _OPENDIR_FLAGS : linux.Open_Flags : {.NONBLOCK, .DIRECTORY, .LARGEFILE, .CLOEXEC}
 
 _is_path_separator :: proc(c: byte) -> bool {
-	return c == '/'
+	return c == _Path_Separator
 }
 
 _mkdir :: proc(path: string, perm: int) -> Error {