In Gforth 1.0 and following, you can use \c, c-function
and add-lib only inside
c-library...end-c-library. add-lib now always
starts from a clean slate inside a c-library, so you don’t need
to use clear-libs in most cases.
If you have a program that uses these words outside
c-library...end-c-library, just wrap them in
c-library...end-c-library. You may have to add some
instances of add-lib, however.