diff --git a/src/gccode.c b/src/gccode.c
index 433a162..cad9f19 100644
--- a/src/gccode.c
+++ b/src/gccode.c
@@ -69,6 +69,7 @@ typedef struct implicit_key_hash_table {
 } Ikhashtbl;
 #endif
 
+extern unsigned int oplength[256];
 #ifdef BIGVM
 /* Table of opcode lengths for 4-byte atom opcode cases */
 #define LONGEST_OPCODE 5