diff --git a/include/bits.c b/include/bits.c
index 447e4d977..7e76828b4 100644
--- a/include/bits.c
+++ b/include/bits.c
@@ -281,6 +281,14 @@ int main(int argc, char **argv)
     fprintf(f, "#endif\n");
     fprintf(f, "#endif\n");
 
+    fprintf(f, "#ifndef HEIMDAL_UNUSED_ATTRIBUTE\n");
+    fprintf(f, "#if defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1 )))\n");
+    fprintf(f, "#define HEIMDAL_UNUSED_ATTRIBUTE __attribute__((unused))\n");
+    fprintf(f, "#else\n");
+    fprintf(f, "#define HEIMDAL_UNUSED_ATTRIBUTE\n");
+    fprintf(f, "#endif\n");
+    fprintf(f, "#endif\n");
+
     fprintf(f, "#endif /* %s */\n", hb);
 
     if (f != stdout)
diff --git a/include/krb5-types.cross b/include/krb5-types.cross
index a30632fae..6f67443ba 100644
--- a/include/krb5-types.cross
+++ b/include/krb5-types.cross
@@ -39,6 +39,14 @@ typedef ssize_t krb5_ssize_t;
 #endif
 #endif
 
+#ifndef HEIMDAL_UNUSED_ATTRIBUTE
+#if defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1 )))
+#define HEIMDAL_UNUSED_ATTRIBUTE __attribute__((unused))
+#else
+#define HEIMDAL_UNUSED_ATTRIBUTE
+#endif
+#endif
+
 typedef int krb5_socket_t;
 
 #endif /* __krb5_types_h__ */
diff --git a/lib/asn1/gen_decode.c b/lib/asn1/gen_decode.c
index c4acb493c..9d816d540 100644
--- a/lib/asn1/gen_decode.c
+++ b/lib/asn1/gen_decode.c
@@ -609,7 +609,7 @@ decode_type (const char *name, const Type *t, int optional,
 		    "(%s)->element = %s;\n"
 		    "p += len;\n"
 		    "ret += len;\n"
-		    "len -= len;\n"
+		    "len = 0;\n"
 		    "}\n",
 		    name, have_ellipsis->gen_name,
 		    name, have_ellipsis->gen_name,
@@ -666,8 +666,8 @@ generate_type_decode (const Symbol *s)
     int preserve = preserve_type(s->name) ? TRUE : FALSE;
 
     fprintf (codefile, "int ASN1CALL\n"
-	     "decode_%s(const unsigned char *p,"
-	     " size_t len, %s *data, size_t *size)\n"
+	     "decode_%s(const unsigned char *p HEIMDAL_UNUSED_ATTRIBUTE,"
+	     " size_t len HEIMDAL_UNUSED_ATTRIBUTE, %s *data, size_t *size)\n"
 	     "{\n",
 	     s->gen_name, s->gen_name);
 
@@ -698,8 +698,8 @@ generate_type_decode (const Symbol *s)
     case TChoice:
 	fprintf (codefile,
 		 "size_t ret = 0;\n"
-		 "size_t l;\n"
-		 "int e;\n");
+		 "size_t l HEIMDAL_UNUSED_ATTRIBUTE;\n"
+		 "int e HEIMDAL_UNUSED_ATTRIBUTE;\n");
 	if (preserve)
 	    fprintf (codefile, "const unsigned char *begin = p;\n");
 
diff --git a/lib/asn1/gen_encode.c b/lib/asn1/gen_encode.c
index a9d2848a2..1bd47484d 100644
--- a/lib/asn1/gen_encode.c
+++ b/lib/asn1/gen_encode.c
@@ -274,7 +274,7 @@ encode_type (const char *name, const Type *t, const char *tmpstr)
 	    else if(m->defval)
 		gen_compare_defval(s + 1, m->defval);
 	    fprintf (codefile, "{\n");
-	    fprintf (codefile, "size_t %s_oldret = ret;\n", tmpstr);
+	    fprintf (codefile, "size_t %s_oldret HEIMDAL_UNUSED_ATTRIBUTE = ret;\n", tmpstr);
 	    fprintf (codefile, "ret = 0;\n");
 	    encode_type (s, m->type, m->gen_name);
 	    fprintf (codefile, "ret += %s_oldret;\n", tmpstr);
@@ -503,7 +503,7 @@ void
 generate_type_encode (const Symbol *s)
 {
     fprintf (codefile, "int ASN1CALL\n"
-	     "encode_%s(unsigned char *p, size_t len,"
+	     "encode_%s(unsigned char *p HEIMDAL_UNUSED_ATTRIBUTE, size_t len HEIMDAL_UNUSED_ATTRIBUTE,"
 	     " const %s *data, size_t *size)\n"
 	     "{\n",
 	     s->gen_name, s->gen_name);
@@ -534,10 +534,9 @@ generate_type_encode (const Symbol *s)
     case TType:
     case TChoice:
 	fprintf (codefile,
-		 "size_t ret = 0;\n"
-		 "size_t l;\n"
-		 "int i, e;\n\n");
-	fprintf(codefile, "i = 0;\n"); /* hack to avoid `unused variable' */
+		 "size_t ret HEIMDAL_UNUSED_ATTRIBUTE = 0;\n"
+		 "size_t l HEIMDAL_UNUSED_ATTRIBUTE;\n"
+		 "int i HEIMDAL_UNUSED_ATTRIBUTE, e HEIMDAL_UNUSED_ATTRIBUTE;\n\n");
 
 	encode_type("data", s->type, "Top");