[Bug libstdc++/67408] assumes that __gthread_mutex_t and__gthread_recursive_mutex_t are the same types

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67408

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Created attachment 36276
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36276&action=edit
Handle recursive mutexes with different types.

Does this work for your target?