Gold

gold is a new linker intended as a replacement for the ld.bfd linker.

The two installed linkers are available directly as ld.bfd and ld.gold respectively. Additionally, the default linker is also installed as ld -- and this binary is used by compilers.

The easy way
Emerge binutils-config and set default linker to gold (version 3+ that is marked as ~testing as of 03/2k11):

The hard way (manually)
The default linker can be changed immediately by linking ld to ld.gold in the binutils directory.

Hard link:

Symbolic link:

To make the change persistent across re-installations of binutils, one should pass a flag to the binutils configure script. This can be done using the EXTRA_ECONF variable in a package.env configuration.