Somewhere there are chip designers thinking they can create the first processor on which NetBSD cannot run. Have fun kids: many have tried that and failed!
Not every chip mimics a PDP-11 or can be made to resemble one. Chuck Moore's GA144 is an array of his F18A Forth chips, which are all rather small and simple stack machines that support such fine grained operations as looping the instructions that share a machine word.
Given that this is a heavily segmented machine, with very different primitive operations than a PDP-11, and also has a word size of eighteen, I don't imagine C would run very well on it at all, if you even wanted to try.
I'd say that the stack machine in the GA144 is feasible to compile normal C to. And the 18-bit word is barely a problem. But the (complete lack of) memory architecture is a clear dealbreaker. There's no compiling a normal C program down to an architecture that has 64 words of RAM. At best you can gang a few cores together to make an emulator for a simple virtual machine.
Given that this is a heavily segmented machine, with very different primitive operations than a PDP-11, and also has a word size of eighteen, I don't imagine C would run very well on it at all, if you even wanted to try.
So, there you have it.