[build] remove ENABLE_WALLET ifdef from httprpc.cpp

src/walletinitinterface.h

@@ -12,6 +12,8 @@ class CRPCTable;
 
 class WalletInitInterface {
 public:
+    /** Is the wallet component enabled */
+    virtual bool HasWalletSupport() const = 0;
     /** Get wallet help string */
     virtual void AddWalletOptions() const = 0;
     /** Check wallet parameter interaction */
@@ -34,4 +36,6 @@ public:
     virtual ~WalletInitInterface() {}
 };
 
+extern const WalletInitInterface& g_wallet_init_interface;
+
 #endif // BITCOIN_WALLETINITINTERFACE_H