"C9" constructors in mangled names

[Dan Kegel]

I ran into a bunch of symbols coming out of g++ 4.6.3 + coverity
that c++filt couldn't handle:

_ZN6oblong5media4TopeC9ERKS1_
_ZN6oblong6plasma8HoseGangC9Ev

etc.  Oddly, when I tried to reproduce the build more simply, all I
could generate
were names that had C1 and C2 in them, not C9.
Piping the symbols through sed s/C9/C1/ before cfilt++ made everything happy.

I did find one mention about this,
http://software.intel.com/en-us/forums/topic/302117
so it isn't just me :-)

Should binutils handle the C9 symbols?  What is it that triggers gcc
to generate them?