fixed memory fault, adapted mechanism code_scope

lang/cem/cemcom/expr.c

@@ -22,6 +22,7 @@
 #include	"sizes.h"
 #include	"level.h"
 #include	"noRoption.h"
+#include	"use_tmp.h"
 
 extern char *symbol2str();
 extern char options[];
@@ -183,7 +184,12 @@ idf2expr(expr)
 	}
 	else {
 #ifndef	LINT
-		def->df_used = 1;
+		if (! def->df_used) {
+			def->df_used = 1;
+#ifndef PREPEND_SCOPES
+			code_scope(idf->id_text, def);
+#endif PREPEND_SCOPES
+		}
 #endif	LINT
 		expr->ex_type = def->df_type;
 		if (expr->ex_type == error_type)