The Linux kernel is dependent on glibc, so I would bet that it is vulnerable. I'm curious to see how this plays out.
Does the Linux kernel code use glibc? I thought it was more of a system-level library (like win32.dll for instance) that almost every application on the system has hooks into. Obviously, on a system that uses the system's central libraries, it's enough to just patch the library and be done, but of course this doesn't rule out statically-linked applications, or apps that ship with their own version of glibc.so (don't know how prevalent that is)
I've done a little reading, and apparently, many router vendors use a more compact library than glibc for embedded systems, so these platforms aren't affected. I don't know if Mikrotik is such a system or not - waiting for Normis et. al.