util: Replace boost::signals2 with std::function

src/test/test_bitcoin_fuzzy.cpp

@@ -6,20 +6,20 @@
 #include <config/bitcoin-config.h>
 #endif
 
-#include <consensus/merkle.h>
-#include <primitives/block.h>
-#include <script/script.h>
 #include <addrman.h>
+#include <blockencodings.h>
 #include <chain.h>
 #include <coins.h>
 #include <compressor.h>
+#include <consensus/merkle.h>
 #include <net.h>
+#include <primitives/block.h>
 #include <protocol.h>
+#include <pubkey.h>
+#include <script/script.h>
 #include <streams.h>
 #include <undo.h>
 #include <version.h>
-#include <pubkey.h>
-#include <blockencodings.h>
 
 #include <stdint.h>
 #include <unistd.h>
@@ -28,6 +28,8 @@
 #include <memory>
 #include <vector>
 
+const std::function<std::string(const char*)> G_TRANSLATION_FUN = nullptr;
+
 enum TEST_ID {
     CBLOCK_DESERIALIZE=0,
     CTRANSACTION_DESERIALIZE,