Add schnorrsig module which implements BIP-schnorr [0] compatible signing, verification and batch verification.

[0] https://github.com/sipa/bips/blob/bip-schnorr/bip-schnorr.mediawiki

src/tests.c

@@ -5431,6 +5431,10 @@ void run_ecdsa_openssl(void) {
 # include "modules/ecdh/tests_impl.h"
 #endif
 
+#ifdef ENABLE_MODULE_SCHNORRSIG
+# include "modules/schnorrsig/tests_impl.h"
+#endif
+
 #ifdef ENABLE_MODULE_RECOVERY
 # include "modules/recovery/tests_impl.h"
 #endif
@@ -5743,6 +5747,11 @@ int main(int argc, char **argv) {
     run_ecdh_tests();
 #endif
 
+#ifdef ENABLE_MODULE_SCHNORRSIG
+    /* Schnorrsig tests */
+    run_schnorrsig_tests();
+#endif
+
     /* ecdsa tests */
     run_random_pubkeys();
     run_ecdsa_der_parse();