For a few things like system DNS resolver in net package (can be switched to the pure Go version with compile-time or run-time switch) and getting user's home directory in os/user package.
At a computer with go1.4.2 freebsd/amd64 ATM (earlier was go1.8.1 linux/amd64 IIRC) and the above os/user example results in a dynamically linked ELF when built with CGO_ENABLED set to 0.