Changed codegen for postfix inc/dec operations by deferring them till sequence points.

This usually allows faster & smaller code.
Note that deferred operations must still be called at sequence points even if the whole expressions containing them had constant values.

src/cc65/compile.c

@@ -320,6 +320,9 @@ static void Parse (void)
                 } else {
                     /* Parse the function body */
                     NewFunc (Entry, FuncDef);
+
+                    /* Make sure we aren't omitting any work */
+                    CheckDeferredOpAllDone ();
                 }
             }
 
@@ -395,6 +398,8 @@ void Compile (const char* FileName)
     /* DefineNumericMacro ("__STDC__", 1);      <- not now */
     DefineNumericMacro ("__STDC_HOSTED__", 1);
 
+    InitDeferredOps ();
+
     /* Create the base lexical level */
     EnterGlobalLevel ();
 
@@ -486,6 +491,8 @@ void Compile (const char* FileName)
         }
     }
 
+    DoneDeferredOps ();
+
     if (Debug) {
         PrintMacroStats (stdout);
     }