BUG: Fix typo error in CMake/ExternalProject.cmake

CMake/ExternalProject.cmake

@@ -685,7 +685,7 @@ function(_ep_add_download_command name)
   elseif(git_repository)
     #find_package(Git)
     find_program(Git_EXECUTABLE git DOC "git command line client")
-    mars_as_advanced(Git_EXECUTABLE)
+    mark_as_advanced(Git_EXECUTABLE)
     if(NOT Git_EXECUTABLE)
       message(FATAL_ERROR "error: could not git svn for clone of ${name}")
     endif()