[Trisquel-users] Re : libstdc++6 version 4.9 or newer needed in the repositories

[lcerf]

You can get it from a PPA (which is supposed to only contain free software,  
but you will use it at your own risks):
$ sudo add-apt-repository ppa:ubuntu-toolchain-r/test
$ sudo apt-get update
$ sudo apt-get install libstdc++6