steps on the way to have the callee check the number of arguments

* libguile/_scm.h (SCM_OBJCODE_MINOR_VERSION): Bump.

* libguile/vm-i-system.c (assert-nargs-ee, assert-nargs-ge)
  (push-rest-list): New instructions, which for now don't actually do
  anything. Renumber the rest of the ops in this file.

* module/language/glil.scm (<glil-arity>): New GLIL type, an entity that
  checks the number of args for a block, optionally consing a rest list,
  and either branching or erroring if the arity doesn't match.

* module/language/glil/compile-assembly.scm (glil->assembly): Compile
  <glil-arity> to assembly. Some of these VM ops are not implemented --
  notably the branching case.

* module/language/tree-il/compile-glil.scm (flatten-lambda): Emit
  <glil-arity>.

* test-suite/tests/tree-il.test: Update.

module/language/glil.scm

@@ -27,6 +27,9 @@
    glil-program-nargs glil-program-nrest glil-program-nlocs
    glil-program-meta glil-program-body
    
+   <glil-arity> make-glil-arity glil-arity?
+   glil-arity-nargs glil-arity-nrest glil-arity-label
+
    <glil-bind> make-glil-bind glil-bind?
    glil-bind-vars
 
@@ -72,6 +75,7 @@
 (define-type (<glil> #:printer print-glil)
   ;; Meta operations
   (<glil-program> nargs nrest nlocs meta body)
+  (<glil-arity> nargs nrest label)
   (<glil-bind> vars)
   (<glil-mv-bind> vars rest)
   (<glil-unbind>)
@@ -95,6 +99,7 @@
   (pmatch x
     ((program ,nargs ,nrest ,nlocs ,meta . ,body)
      (make-glil-program nargs nrest nlocs meta (map parse-glil body)))
+    ((arity ,nargs ,nrest ,label) (make-glil-arity nargs nrest label))
     ((bind . ,vars) (make-glil-bind vars))
     ((mv-bind ,vars ,rest) (make-glil-mv-bind vars rest))
     ((unbind) (make-glil-unbind))
@@ -116,6 +121,7 @@
     ;; meta
     ((<glil-program> nargs nrest nlocs meta body)
      `(program ,nargs ,nrest ,nlocs ,meta ,@(map unparse-glil body)))
+    ((<glil-arity> nargs nrest label) `(arity ,nargs ,nrest ,label))
     ((<glil-bind> vars) `(bind ,@vars))
     ((<glil-mv-bind> vars rest) `(mv-bind ,vars ,rest))
     ((<glil-unbind>) `(unbind))