fix include paths in all the -zkp modules

This is causing out-of-tree build failures in Elements.

src/modules/surjection/main_impl.h

@@ -13,11 +13,11 @@
 #include "libsecp256k1-config.h"
 #endif
 
-#include "include/secp256k1_rangeproof.h"
-#include "include/secp256k1_surjectionproof.h"
-#include "modules/rangeproof/borromean.h"
-#include "modules/surjection/surjection_impl.h"
-#include "hash.h"
+#include "../../../include/secp256k1_rangeproof.h"
+#include "../../../include/secp256k1_surjectionproof.h"
+#include "../rangeproof/borromean.h"
+#include "surjection_impl.h"
+#include "../../hash.h"
 
 #ifdef USE_REDUCED_SURJECTION_PROOF_SIZE
 #undef SECP256K1_SURJECTIONPROOF_MAX_USED_INPUTS

src/modules/surjection/surjection.h

@@ -7,8 +7,8 @@
 #ifndef _SECP256K1_SURJECTION_H_
 #define _SECP256K1_SURJECTION_H_
 
-#include "group.h"
-#include "scalar.h"
+#include "../../group.h"
+#include "../../scalar.h"
 
 SECP256K1_INLINE static int secp256k1_surjection_genmessage(unsigned char *msg32, secp256k1_ge *ephemeral_input_tags, size_t n_input_tags, secp256k1_ge *ephemeral_output_tag);
 

src/modules/surjection/surjection_impl.h

@@ -10,10 +10,10 @@
 #include <assert.h>
 #include <string.h>
 
-#include "eckey.h"
-#include "group.h"
-#include "scalar.h"
-#include "hash.h"
+#include "../../eckey.h"
+#include "../../group.h"
+#include "../../scalar.h"
+#include "../../hash.h"
 
 SECP256K1_INLINE static void secp256k1_surjection_genmessage(unsigned char *msg32, const secp256k1_generator *ephemeral_input_tags, size_t n_input_tags, const secp256k1_generator *ephemeral_output_tag) {
     /* compute message */

src/modules/surjection/tests_impl.h

@@ -7,11 +7,11 @@
 #ifndef SECP256K1_MODULE_SURJECTIONPROOF_TESTS
 #define SECP256K1_MODULE_SURJECTIONPROOF_TESTS
 
-#include "testrand.h"
-#include "group.h"
-#include "include/secp256k1_generator.h"
-#include "include/secp256k1_rangeproof.h"
-#include "include/secp256k1_surjectionproof.h"
+#include "../../testrand.h"
+#include "../../group.h"
+#include "../../../include/secp256k1_generator.h"
+#include "../../../include/secp256k1_rangeproof.h"
+#include "../../../include/secp256k1_surjectionproof.h"
 
 static void test_surjectionproof_api(void) {
     unsigned char seed[32];