change local lib headers to be relative for those pointing at "include/" dir

added relative paths to header files imported from src directory

added include guards for contrib/ files when referring to secp256k1.h

src/modules/schnorrsig/main_impl.h

@@ -7,9 +7,9 @@
 #ifndef SECP256K1_MODULE_SCHNORRSIG_MAIN_H
 #define SECP256K1_MODULE_SCHNORRSIG_MAIN_H
 
-#include "include/secp256k1.h"
-#include "include/secp256k1_schnorrsig.h"
-#include "hash.h"
+#include "../../../include/secp256k1.h"
+#include "../../../include/secp256k1_schnorrsig.h"
+#include "../../hash.h"
 
 /* Initializes SHA256 with fixed midstate. This midstate was computed by applying
  * SHA256 to SHA256("BIP0340/nonce")||SHA256("BIP0340/nonce"). */

src/modules/schnorrsig/tests_exhaustive_impl.h

@@ -7,7 +7,7 @@
 #ifndef SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_H
 #define SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_H
 
-#include "include/secp256k1_schnorrsig.h"
+#include "../../../include/secp256k1_schnorrsig.h"
 #include "src/modules/schnorrsig/main_impl.h"
 
 static const unsigned char invalid_pubkey_bytes[][32] = {

src/modules/schnorrsig/tests_impl.h

@@ -7,7 +7,7 @@
 #ifndef SECP256K1_MODULE_SCHNORRSIG_TESTS_H
 #define SECP256K1_MODULE_SCHNORRSIG_TESTS_H
 
-#include "secp256k1_schnorrsig.h"
+#include "../../../include/secp256k1_schnorrsig.h"
 
 /* Checks that a bit flip in the n_flip-th argument (that has n_bytes many
  * bytes) changes the hash function