Alan Modra added the "INSERT" command to the BFD based linker back in 2008, but no corresponding support was added to gold. Given INSERT was designed to make it easier to augment the default linker script, it may not make sense for gold. I'm really not in a position to make that decision.
*** Bug 19326 has been marked as a duplicate of this bug. ***
*** Bug 20870 has been marked as a duplicate of this bug. ***
*** Bug 21676 has been marked as a duplicate of this bug. ***