(byte-compile-eval): Adjust to changes in `load-history`

(byte-compile-eval): Adjust to changes in `load-history`

The `function-history` patch introduced a regression which caused
spurious compiler warnings.  Fix it.
The new code also fixes a bug in the old code, thus causing some
new non-spurious warnings.  Fix them as well.

* lisp/emacs-lisp/bytecomp.el (byte-compile-eval): Adjust to changes in
`load-history`.

* lisp/gnus/gnus-group.el (nnrss-discover-feed)
(nnrss-save-server-data): Use `declare-function`.

* lisp/cedet/semantic/wisent/comp.el (wisent-defcontext)
(wisent-with-context):
* lisp/emacs-lisp/comp.el (comp-op-case): Silence compiler warning.