cmp: use correctly with-exit-label

Previusly we've duplicated some code with regard to this macro, most notably
we've bound *exit* separately to label instead of passing it as a first arg.

src/cmp/cmpbackend-cxx/cmpc-util.lsp

@@ -93,6 +93,7 @@
          (*max-temp* 0)
          (*next-cfun* 0)
          (*last-label* 0)
+         (*unwind-exit* nil)
          (*inline-information*
            (ext:if-let ((r (machine-inline-information *machine*)))
              (si:copy-hash-table r)

src/cmp/cmpbackend-cxx/cmppass2-call.lsp

@@ -101,12 +101,10 @@
              (tail-recursion-possible)
              (inline-possible (fun-name fun))
              (= (length args) (length (rest *tail-recursion-info*))))
-    (let* ((*destination* 'TRASH)
-           (*exit* (next-label))
-           (*unwind-exit* (cons *exit* *unwind-exit*)))
-      (c2psetq nil ;; We do not provide any C2FORM
-               (cdr *tail-recursion-info*) args)
-      (wt-label *exit*))
+    (with-exit-label (*exit*)
+      (let ((*destination* 'TRASH))
+        ;; We do not provide any C2FORM.
+        (c2psetq nil (cdr *tail-recursion-info*) args)))
     (unwind-no-exit 'TAIL-RECURSION-MARK)
     (wt-nl "goto TTL;")
     (cmpdebug "Tail-recursive call of ~s was replaced by iteration."

src/cmp/cmpbackend-cxx/cmppass2-cont.lsp

@@ -164,9 +164,8 @@
             (wt-nl "if (__ecl_frs_push_result) {")
             (wt-comment "BEGIN CATCH ~A" code)
             (with-indentation
-              (with-exit-label (label)
-                (let ((*exit* label))
-                  (unwind-exit 'VALUES))))
+              (with-exit-label (*exit*)
+                (unwind-exit 'VALUES)))
             (wt-nl "} else {")
             (with-indentation
               (c2expr* body)))))

src/cmp/cmpbackend-cxx/cmppass2-eval.lsp

@@ -26,12 +26,10 @@
   ;; other expressions will follow this one. We must thus create
   ;; a possible label so that the compiled forms exit right at
   ;; the point where the next form will be compiled.
-  (with-exit-label (label)
-    (let* ((*exit* label)
-           (*unwind-exit* (cons *exit* *unwind-exit*))
-           ;;(*lex* *lex*)
-           (*lcl* *lcl*)
-           (*temp* *temp*))
+  (with-exit-label (*exit*)
+    (let (;;(*lex* *lex*)
+          (*lcl* *lcl*)
+          (*temp* *temp*))
       (c2expr form))))
 
 (defun c2progn (c1form forms)

src/cmp/cmpbackend-cxx/cmppass2-top.lsp

@@ -245,35 +245,27 @@
 
 (defun t2ordinary (c1form form)
   (declare (ignore c1form))
-  (let* ((*exit* (next-label))
-         (*unwind-exit* (list *exit*))
-         (*destination* 'TRASH))
-    (c2expr form)
-    (wt-label *exit*)))
+  (with-exit-label (*exit*)
+    (let ((*destination* 'TRASH))
+      (c2expr form))))
 
 (defun t2load-time-value (c1form vv-loc form)
   (declare (ignore c1form))
-  (let* ((*exit* (next-label))
-         (*unwind-exit* (list *exit*))
-         (*destination* vv-loc))
-    (c2expr form)
-    (wt-label *exit*)))
+  (with-exit-label (*exit*)
+    (let ((*destination* vv-loc))
+      (c2expr form))))
 
 (defun t2make-form (c1form vv-loc form)
   (declare (ignore c1form))
-  (let* ((*exit* (next-label))
-         (*unwind-exit* (list *exit*))
-         (*destination* vv-loc))
-    (c2expr form)
-    (wt-label *exit*)))
+  (with-exit-label (*exit*)
+    (let ((*destination* vv-loc))
+      (c2expr form))))
 
 (defun t2init-form (c1form vv-loc form)
   (declare (ignore c1form vv-loc))
-  (let* ((*exit* (next-label))
-         (*unwind-exit* (list *exit*))
-         (*destination* 'TRASH))
-    (c2expr form)
-    (wt-label *exit*)))
+  (with-exit-label (*exit*)
+    (let ((*destination* 'TRASH))
+      (c2expr form))))
 
 (defun locative-type-from-var-kind (kind)
   (cdr (assoc kind