[Bug libstdc++/47437] libstdc++ parallel mode: multiway_merge does not compile

[singler at kit dot edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47437

--- Comment #1 from Johannes Singler <singler at kit dot edu> 2011-01-24 14:48:42 UTC ---
Created attachment 23101
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23101
Remove mutable qualifier from reference member.