all of guile compiles now, expanded with syncase

* libguile/eval.c (scm_m_eval_when): Whoops, eval-when has an implicit
  begin. Fix.

* module/oop/goops.scm: Syncase doesn't like definitions in expression
  context, and grudgingly I have decided to go along with that. But that
  doesn't mean we can't keep the old semantics, via accessing the module
  system directly. So do so. I took the opportunity to rewrite some
  macros with syntax-rules and syntax-case -- the former is nicer than
  the latter, of course.

* module/oop/goops/save.scm: Don't define within an expression.

* module/oop/goops/simple.scm (define-class): Use define-syntax.

* module/oop/goops/stklos.scm (define-class): Use define-syntax.

module/oop/goops/simple.scm

@@ -23,6 +23,9 @@
   :export (define-class)
   :no-backtrace)
 
-(define define-class define-class-with-accessors-keywords)
+(define-syntax define-class
+  (syntax-rules ()
+    ((_ arg ...)
+     (define-class-with-accessors-keywords arg ...))))
 
 (module-use! %module-public-interface (resolve-interface '(oop goops)))