g++ Linker errors after upgrading to gcc-4.8 on Debian, libc6

Question

I have just dist-upgraded a Debian Weezy machine to run gcc-4.8 from gcc-4.7. Previously the build environment was sane and was compiling normally. Now it gives the follow

Answer 1

Ah! As soon as I finished typing this, as a last ditch, I tried:

apt-get install libc6-dev --reinstall

(although I was convinced I'd already done it previously), and lo and behold, the issue went away!