if my_realpath() fails, don't return the error code, get_defaults_options()
returns a number of options consumed, not 0=ok/1=error.
instead, ignore the error from my_realpath. If it fails it internally
falls back to my_load_path, which restores 10.4- behavior
process all --defaults* options uniformly,
get rid of special case for --no-defaults and --print-defaults
use realpath instead of blindly concatenating pwd and relative path.
