Hello,

The Emacs integrated development environments Slime and Sly
communicate by means of similar RPC protocols with different server
programs: Swank in case of Slime and Slynk in case of Sly.  However,
the code in org-babel-execute:lisp always expects to talk with Swank
because of the hard-coded call to swank:eval-and-grab-output.

After starting a Sly REPL, calls to swank:eval-and-grab-output do not
talk with the Slynk server started by the Sly REPL.

The attached patch "soft-codes" eval-and-grab-output to become
swank:eval-and-grab-output when using Slime and
slynk:eval-and-grab-output when using Sly.

For more info: steps to test the patch are:
1. Open a Sly REPL with M-x sly
2. Look in the *sly-events for <LISP>* (<LISP> is sbcl in my case) for
    slynk: prefixes
3. Type C-c C-c on the test block below
4. Look for an addition in *sly-events for <LISP>* looking like
    (slynk:eval-and-grab-output "(let ((...)) (+ 1 1)\n)")

#+name: test-ob-lisp-with-sly
#+begin_src lisp -n :output results
(+ 1 1)
#+end_src

#+RESULTS: test-ob-lisp-with-sly
: 2

Best regards -- Gerard