basic: fold getopt-defs.h into proc-cmdline.c

basic: fold getopt-defs.h into proc-cmdline.c

It'd be nice if we could not repeat the information about the option
list a second time. But I don't see a nice way to do this, since
(by design) with the macro approach, the macros must be intertwined
with the parse_argv() code. But that code in turn refers to a bunch
of variables, so lifting out the function is not immediately possible.
So I think it's best to keep the existing approach where we provide
a list of options, without additional context, and skip them using
a custom routine.