https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69191
--- Comment #11 from eyenseo at gmail dot com --- (In reply to Jonathan Wakely from comment #10) > Use ldd to see which library is used at runtime. See what file that symlink > points to. Compare with the version numbers of the releases. > > GCC 4.9.0: libstdc++.so.6.0.20 > > GCC 5.1.0: libstdc++.so.6.0.21 Ok will do on Monday