diff --git a/include/cyclone/types.h b/include/cyclone/types.h
index f881fc03..36fada11 100644
--- a/include/cyclone/types.h
+++ b/include/cyclone/types.h
@@ -673,8 +673,11 @@ typedef union {
 void **vpbuffer_realloc(void **buf, int *len);
 void **vpbuffer_add(void **buf, int *len, int i, void *obj);
 void vpbuffer_free(void **buf);
+
+/* Bignum utility functions */
 double mp_get_double(mp_int *a);
 int Cyc_bignum_cmp(bn_cmp_type type, object x, int tx, object y, int ty);
+void Cyc_int2bignum(int n, mp_int *bn);
 
 /* GC prototypes */
 void gc_initialize();
diff --git a/runtime.c b/runtime.c
index 0bff92dd..ac97fd61 100644
--- a/runtime.c
+++ b/runtime.c
@@ -1233,7 +1233,7 @@ object Cyc_bignum_normalize(void *data, object n)
   return result;
 }
 
-static void Cyc_int2bignum(int n, mp_int *bn)
+void Cyc_int2bignum(int n, mp_int *bn)
 {
   mp_set_int(bn, abs(n));
   if (n < 0) {