[Bug libstdc++/94069] [9 Regression] doesn't compile unless PTHREAD_RWLOCK_INITIALIZER is defined

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94069

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed in commit r10-7064-gb0815713a32c5cc062bd41fa75dac4d4408215fb but I put
the wrong PR number in the commit log.