[Bug libstdc++/47792] [4.6 Regression] concurrence.h:292:9: error: '__gthread_mutex_destroy' was not declared in this scope

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47792

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-02-18 
00:23:32 UTC ---
why is __GTHREADS defined for thread model 'single' - is that normal?

and why isn't __gthread_mutex_destroy in gthr-single.h in scope?