[Bug fortran/99529] libgfortran I/O: Data races related to new unit / new unit calls for I/O to strings

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99529

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Or make an internal (static) newunit_free_unlocked and make the exported
newunit_free take the lock.