fix various compiler warnings

Change-Id: I65a862132563f578eff11b8d085960b820f5d4b7
diff --git a/src/hdlc-test.c b/src/hdlc-test.c
index 1c7c6ef..0814ca0 100644
--- a/src/hdlc-test.c
+++ b/src/hdlc-test.c
@@ -12,12 +12,11 @@
 	int string_len = strlen(hex);
 	int byte_len = string_len/2;
 	int bit_len = byte_len*8;
-	int rc;
 
 	printf("hex string   = %s\n", hex);
 	bytes = alloca(byte_len);
 	bits = alloca(bit_len);
-	rc = osmo_hexparse(hex, bytes, byte_len);
+	osmo_hexparse(hex, bytes, byte_len);
 	printf("parsed bytes = %s\n", osmo_hexdump(bytes, byte_len));
 
 	printf("MSB mode\n");