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/extrakeys/main_impl.h

@@ -7,8 +7,8 @@
 #ifndef SECP256K1_MODULE_EXTRAKEYS_MAIN_H
 #define SECP256K1_MODULE_EXTRAKEYS_MAIN_H
 
-#include "include/secp256k1.h"
-#include "include/secp256k1_extrakeys.h"
+#include "../../../include/secp256k1.h"
+#include "../../../include/secp256k1_extrakeys.h"
 
 static SECP256K1_INLINE int secp256k1_xonly_pubkey_load(const secp256k1_context* ctx, secp256k1_ge *ge, const secp256k1_xonly_pubkey *pubkey) {
     return secp256k1_pubkey_load(ctx, ge, (const secp256k1_pubkey *) pubkey);

src/modules/extrakeys/tests_exhaustive_impl.h

@@ -8,7 +8,7 @@
 #define SECP256K1_MODULE_EXTRAKEYS_TESTS_EXHAUSTIVE_H
 
 #include "src/modules/extrakeys/main_impl.h"
-#include "include/secp256k1_extrakeys.h"
+#include "../../../include/secp256k1_extrakeys.h"
 
 static void test_exhaustive_extrakeys(const secp256k1_context *ctx, const secp256k1_ge* group) {
     secp256k1_keypair keypair[EXHAUSTIVE_TEST_ORDER - 1];

src/modules/extrakeys/tests_impl.h

@@ -7,7 +7,7 @@
 #ifndef SECP256K1_MODULE_EXTRAKEYS_TESTS_H
 #define SECP256K1_MODULE_EXTRAKEYS_TESTS_H
 
-#include "secp256k1_extrakeys.h"
+#include "../../../include/secp256k1_extrakeys.h"
 
 static secp256k1_context* api_test_context(int flags, int *ecount) {
     secp256k1_context *ctx0 = secp256k1_context_create(flags);