I had the same yesterday - run:

> LD_LIBRARY_PATH=/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.3/ ldconfig
> to fix your system.
>
> Thanx to chithanh for this life-saving oneliner
> (http://forums.gentoo.org/viewtopic-p-7053126.html).
>
> Greetings,
> Daniel
>
>
That didnt help the gcc-config error, and also i notice that there's bits
of 4.7.2 still around;

 # ls -l /lib64/libgcc*
-rwxr-xr-x 1 root root 88720 May 16 21:13
/lib64/libgcc_s-4.7.2-20121109.so.1
lrwxrwxrwx 1 root root    28 May 17 01:19 /lib64/libgcc_s.so.1 ->
libgcc_s-4.7.2-20121109.so.1