GCC PR libstdc++/66145 is a regression in GCC 5 which won't be fixed
upstream in time for the GCC defaults change.  The work around is to
rebuild the affected packages after GCC 5 is the default compiler.
Please look at the code and decide, if the package is affected. If
not, please just close the issue.  If it's a real issue, I'll add
the packages affected to libstdc++6's Breaks attributes, with the
version of the package at the time of the defaults change.

See https://wiki.debian.org/GCC5#libstdc.2B-.2B-_c.2B-.2B-11_incompatibilities_.284.9_and_5.29
for further information.

To build with GCC 5,install the gcc, g++, gfortran, ... packages
from experimental (apt-get -t experimental install g++).