set! name (lambda ...) names the lambda

set! name (lambda ...) names the lambda

* module/ice-9/psyntax.scm (build-lexical-assignment)
  (build-global-assignment): Maybe name the RHS.

* module/ice-9/psyntax-pp.scm: Regenerated.

* module/ice-9/boot-9.scm (catch, with-throw-handler, throw): Rework to
  use set! instead of define! so that we get names.