Include public module headers when compiling modules.

Also fix the nullness requirements for schnorr nonce-pair generation.

src/modules/ecdh/main_impl.h

@@ -7,6 +7,7 @@
 #ifndef _SECP256K1_MODULE_ECDH_MAIN_
 #define _SECP256K1_MODULE_ECDH_MAIN_
 
+#include "include/secp256k1_ecdh.h"
 #include "ecmult_const_impl.h"
 
 int secp256k1_ecdh(const secp256k1_context* ctx, unsigned char *result, const secp256k1_pubkey *point, const unsigned char *scalar) {

src/modules/schnorr/main_impl.h

@@ -7,6 +7,7 @@
 #ifndef SECP256K1_MODULE_SCHNORR_MAIN
 #define SECP256K1_MODULE_SCHNORR_MAIN
 
+#include "include/secp256k1_schnorr.h"
 #include "modules/schnorr/schnorr_impl.h"
 
 static void secp256k1_schnorr_msghash_sha256(unsigned char *h32, const unsigned char *r32, const unsigned char *msg32) {

src/modules/schnorr/schnorr.h

@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php. *
  ***********************************************************************/
 
-#ifndef _SECP256K1_SCHNORR_
-#define _SECP256K1_SCHNORR_
+#ifndef _SECP256K1_MODULE_SCHNORR_H_
+#define _SECP256K1_MODULE_SCHNORR_H_
 
 #include "scalar.h"
 #include "group.h"

src/modules/schnorr/tests_impl.h

@@ -7,6 +7,8 @@
 #ifndef SECP256K1_MODULE_SCHNORR_TESTS
 #define SECP256K1_MODULE_SCHNORR_TESTS
 
+#include "include/secp256k1_schnorr.h"
+
 void test_schnorr_end_to_end(void) {
     unsigned char privkey[32];
     unsigned char message[32];