c: Don't break prematurely

This was intended to capture EOFs when entering characters during the
execution of a brainfuck program, but it shouldn't happen here, but
rather in bf_in().

I'm not actually sure how to terminate input to a brainfuck program;
still trying to work that out across all versions.
c/obj: Swallow \n when entering input

Otherwise, the prompt is printed twice (since the \n has not yet
been consumed).
c: Make internal functions static