We are getting there with the rump kernel (rumpkernel.org). It now runs PHP, Lua, LuaJIT, C, C++. This is very much work in progress and it is not particularly user friendly, but it is improving rapidly. I plant to look at Go soon, which has built in syscall traps, which need replacing with library calls. There are a whole bunch of environment assumptions, like existence of dynamic linkers, build systems and so on that need to be worked around.

OSv is another option, it makes life easier by supporting Linux binaries modified to be dynamic libraries, and runs several languages too, although it was initially mainly targeted at JVM languages.