[Bug libstdc++/51906] thread lock test failures on darwin11 under Xcode 4.2

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51906

--- Comment #33 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-01-31 15:27:47 UTC ---
Unsurprising. That code only statically-allocates a mutex, doesn't use C++
non-static data member initializers and doesn't use a recursive mutex (from the
info you've given it seems that all the failures relate to recursive mutexes.)