After merging gcc-3.4.3-r1 the gentoo system does not compile a single line. One needs to enter this command to cure it: gcc-config <number> where <number> is the number of the gcc-3.4.3-r1 configuration. It seems that the ebuild forgets to do this automatically (before this command gcc still tries to use the previous compiler, which does not exist due to unmerging).
what was the previous version of gcc that you had ?
closing due to lack of response.