diff --git a/src/secp256k1/src/modules/schnorrsig/main_impl.h b/src/secp256k1/src/modules/schnorrsig/main_impl.h
index f2b418159..9a08e81d8 100644
--- a/src/secp256k1/src/modules/schnorrsig/main_impl.h
+++ b/src/secp256k1/src/modules/schnorrsig/main_impl.h
@@ -11,6 +11,9 @@
 #include "../../../include/secp256k1_schnorrsig.h"
 #include "hash.h"
 
+static void secp256k1_scalar_chacha20(secp256k1_scalar *r1, secp256k1_scalar *r2, const unsigned char *seed, uint64_t idx);
+static int secp256k1_ecmult_multi_var(const secp256k1_ecmult_context *ctx, secp256k1_scratch *scratch, secp256k1_gej *r, const secp256k1_scalar *inp_g_sc, secp256k1_ecmult_multi_callback cb, void *cbdata, size_t n);
+
 int secp256k1_schnorrsig_serialize(const secp256k1_context* ctx, unsigned char *out64, const secp256k1_schnorrsig* sig) {
     (void) ctx;
     VERIFY_CHECK(ctx != NULL);