It looks like Go supports dynamic linking to "system" libraries. At least on MS Windows this https://code.google.com/p/go/codesearch#go/src/cmd/dist/wind... call to FormatMessageW http://msdn.microsoft.com/en-us/library/windows/desktop/ms67... would be to an implementation in Kernel32.dll that would receive security updates.

On Linux there's a large gray area for things like libexpat.so.1 that may or may not be linked dynamically. But libc is LGPL, so I expect it too would be linked dynamically.