Constrain constant values to a single location in code

src/script/standard.cpp

@@ -16,6 +16,7 @@ using namespace std;
 
 typedef vector<unsigned char> valtype;
 
+bool fAcceptDatacarrier = true;
 unsigned nMaxDatacarrierBytes = MAX_OP_RETURN_RELAY;
 
 CScriptID::CScriptID(const CScript& in) : uint160(Hash160(in.begin(), in.end())) {}