ensure compilation with -std=89 and make constness explicit.
diff --git a/skeletons/OPEN_TYPE_oer.c b/skeletons/OPEN_TYPE_oer.c
index 4823f9d..30bf099 100644
--- a/skeletons/OPEN_TYPE_oer.c
+++ b/skeletons/OPEN_TYPE_oer.c
@@ -77,7 +77,8 @@
     }
 
     if(*memb_ptr2) {
-        asn_CHOICE_specifics_t *specs = selected.type_descriptor->specifics;
+        const asn_CHOICE_specifics_t *specs =
+            selected.type_descriptor->specifics;
         if(elm->flags & ATF_POINTER) {
             ASN_STRUCT_FREE(*selected.type_descriptor, inner_value);
             *memb_ptr2 = NULL;