Merge #19331: build: Do not include server symbols in wallet

faca73000fa8975c28f6be8be01957c1ae94ea62 ci: Install fixed version of clang-format for linters (MarcoFalke)
fa4695da4c69646b58a8fa0b6b30146bb234deb8 build: Sort Makefile.am after renaming file (MarcoFalke)
cccc2784a3bb10fa8e43be7e68207cafb12bd915 scripted-diff: Move ui_interface to the node lib (MarcoFalke)
fa72ca6a9d90d66012765b0043fd819698b94ba8 qt: Remove unused includes (MarcoFalke)
fac96e6450d595fe67168cb7afa7692da6cc9973 wallet: Do not include server symbols (MarcoFalke)
fa0f6c58c1c6d10f04c4e65a424cc51ebca50a8c Revert "Fix link error with --enable-debug" (MarcoFalke)

Pull request description:

  This reverts a hacky workaround from commit b83cc0f, which only happens to work due to compiler optimizations. Then, it actually fixes the linker error.

  The underlying problem is that the wallet includes symbols from the server (ui_interface), which usually results in linker failures. Though, in this specific case the linker failures have not been observed (unless `-O0`) because our compilers were smart enough to strip unused symbols.

  Fix the underlying problem by creating a new header-only with the needed symbol and move ui_interface to node to clarify that this is part of libbitcoin_server.

ACKs for top commit:
  Sjors:
    ACK faca730
  laanwj:
    ACK faca73000fa8975c28f6be8be01957c1ae94ea62
  hebasto:
    re-ACK faca73000fa8975c28f6be8be01957c1ae94ea62, since the [previous](https://github.com/bitcoin/bitcoin/pull/19331#pullrequestreview-434420539) review:

Tree-SHA512: e9731f249425aaea50b6db5fc7622e10078cf006721bb87989cac190a2ff224412f6f8a7dd83efd018835302337611f5839e29e15bef366047ed591cef58dfb4

2 files changed, 186 insertions, 0 deletions

diff --git a/src/node/ui_interface.cpp b/src/node/ui_interface.cpp
new file mode 100644
index 0000000000..9ccd8e27e2
--- /dev/null
+++ b/src/node/ui_interface.cpp
@@ -0,0 +1,65 @@
+// Copyright (c) 2010-2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <node/ui_interface.h>
+
+#include <util/translation.h>
+
+#include <boost/signals2/last_value.hpp>
+#include <boost/signals2/signal.hpp>
+
+CClientUIInterface uiInterface;
+
+struct UISignals {
+    boost::signals2::signal<CClientUIInterface::ThreadSafeMessageBoxSig, boost::signals2::last_value<bool>> ThreadSafeMessageBox;
+    boost::signals2::signal<CClientUIInterface::ThreadSafeQuestionSig, boost::signals2::last_value<bool>> ThreadSafeQuestion;
+    boost::signals2::signal<CClientUIInterface::InitMessageSig> InitMessage;
+    boost::signals2::signal<CClientUIInterface::NotifyNumConnectionsChangedSig> NotifyNumConnectionsChanged;
+    boost::signals2::signal<CClientUIInterface::NotifyNetworkActiveChangedSig> NotifyNetworkActiveChanged;
+    boost::signals2::signal<CClientUIInterface::NotifyAlertChangedSig> NotifyAlertChanged;
+    boost::signals2::signal<CClientUIInterface::ShowProgressSig> ShowProgress;
+    boost::signals2::signal<CClientUIInterface::NotifyBlockTipSig> NotifyBlockTip;
+    boost::signals2::signal<CClientUIInterface::NotifyHeaderTipSig> NotifyHeaderTip;
+    boost::signals2::signal<CClientUIInterface::BannedListChangedSig> BannedListChanged;
+};
+static UISignals g_ui_signals;
+
+#define ADD_SIGNALS_IMPL_WRAPPER(signal_name)                                                                 \
+    boost::signals2::connection CClientUIInterface::signal_name##_connect(std::function<signal_name##Sig> fn) \
+    {                                                                                                         \
+        return g_ui_signals.signal_name.connect(fn);                                                          \
+    }
+
+ADD_SIGNALS_IMPL_WRAPPER(ThreadSafeMessageBox);
+ADD_SIGNALS_IMPL_WRAPPER(ThreadSafeQuestion);
+ADD_SIGNALS_IMPL_WRAPPER(InitMessage);
+ADD_SIGNALS_IMPL_WRAPPER(NotifyNumConnectionsChanged);
+ADD_SIGNALS_IMPL_WRAPPER(NotifyNetworkActiveChanged);
+ADD_SIGNALS_IMPL_WRAPPER(NotifyAlertChanged);
+ADD_SIGNALS_IMPL_WRAPPER(ShowProgress);
+ADD_SIGNALS_IMPL_WRAPPER(NotifyBlockTip);
+ADD_SIGNALS_IMPL_WRAPPER(NotifyHeaderTip);
+ADD_SIGNALS_IMPL_WRAPPER(BannedListChanged);
+
+bool CClientUIInterface::ThreadSafeMessageBox(const bilingual_str& message, const std::string& caption, unsigned int style) { return g_ui_signals.ThreadSafeMessageBox(message, caption, style); }
+bool CClientUIInterface::ThreadSafeQuestion(const bilingual_str& message, const std::string& non_interactive_message, const std::string& caption, unsigned int style) { return g_ui_signals.ThreadSafeQuestion(message, non_interactive_message, caption, style); }
+void CClientUIInterface::InitMessage(const std::string& message) { return g_ui_signals.InitMessage(message); }
+void CClientUIInterface::NotifyNumConnectionsChanged(int newNumConnections) { return g_ui_signals.NotifyNumConnectionsChanged(newNumConnections); }
+void CClientUIInterface::NotifyNetworkActiveChanged(bool networkActive) { return g_ui_signals.NotifyNetworkActiveChanged(networkActive); }
+void CClientUIInterface::NotifyAlertChanged() { return g_ui_signals.NotifyAlertChanged(); }
+void CClientUIInterface::ShowProgress(const std::string& title, int nProgress, bool resume_possible) { return g_ui_signals.ShowProgress(title, nProgress, resume_possible); }
+void CClientUIInterface::NotifyBlockTip(SynchronizationState s, const CBlockIndex* i) { return g_ui_signals.NotifyBlockTip(s, i); }
+void CClientUIInterface::NotifyHeaderTip(SynchronizationState s, const CBlockIndex* i) { return g_ui_signals.NotifyHeaderTip(s, i); }
+void CClientUIInterface::BannedListChanged() { return g_ui_signals.BannedListChanged(); }
+
+bool InitError(const bilingual_str& str)
+{
+    uiInterface.ThreadSafeMessageBox(str, "", CClientUIInterface::MSG_ERROR);
+    return false;
+}
+
+void InitWarning(const bilingual_str& str)
+{
+    uiInterface.ThreadSafeMessageBox(str, "", CClientUIInterface::MSG_WARNING);
+}
diff --git a/src/node/ui_interface.h b/src/node/ui_interface.h
new file mode 100644
index 0000000000..d574ab879f
--- /dev/null
+++ b/src/node/ui_interface.h
@@ -0,0 +1,121 @@
+// Copyright (c) 2010 Satoshi Nakamoto
+// Copyright (c) 2012-2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_NODE_UI_INTERFACE_H
+#define BITCOIN_NODE_UI_INTERFACE_H
+
+#include <functional>
+#include <memory>
+#include <string>
+
+class CBlockIndex;
+enum class SynchronizationState;
+struct bilingual_str;
+
+namespace boost {
+namespace signals2 {
+class connection;
+}
+} // namespace boost
+
+/** Signals for UI communication. */
+class CClientUIInterface
+{
+public:
+    /** Flags for CClientUIInterface::ThreadSafeMessageBox */
+    enum MessageBoxFlags
+    {
+        ICON_INFORMATION    = 0,
+        ICON_WARNING        = (1U << 0),
+        ICON_ERROR          = (1U << 1),
+        /**
+         * Mask of all available icons in CClientUIInterface::MessageBoxFlags
+         * This needs to be updated, when icons are changed there!
+         */
+        ICON_MASK = (ICON_INFORMATION | ICON_WARNING | ICON_ERROR),
+
+        /** These values are taken from qmessagebox.h "enum StandardButton" to be directly usable */
+        BTN_OK      = 0x00000400U, // QMessageBox::Ok
+        BTN_YES     = 0x00004000U, // QMessageBox::Yes
+        BTN_NO      = 0x00010000U, // QMessageBox::No
+        BTN_ABORT   = 0x00040000U, // QMessageBox::Abort
+        BTN_RETRY   = 0x00080000U, // QMessageBox::Retry
+        BTN_IGNORE  = 0x00100000U, // QMessageBox::Ignore
+        BTN_CLOSE   = 0x00200000U, // QMessageBox::Close
+        BTN_CANCEL  = 0x00400000U, // QMessageBox::Cancel
+        BTN_DISCARD = 0x00800000U, // QMessageBox::Discard
+        BTN_HELP    = 0x01000000U, // QMessageBox::Help
+        BTN_APPLY   = 0x02000000U, // QMessageBox::Apply
+        BTN_RESET   = 0x04000000U, // QMessageBox::Reset
+        /**
+         * Mask of all available buttons in CClientUIInterface::MessageBoxFlags
+         * This needs to be updated, when buttons are changed there!
+         */
+        BTN_MASK = (BTN_OK | BTN_YES | BTN_NO | BTN_ABORT | BTN_RETRY | BTN_IGNORE |
+                    BTN_CLOSE | BTN_CANCEL | BTN_DISCARD | BTN_HELP | BTN_APPLY | BTN_RESET),
+
+        /** Force blocking, modal message box dialog (not just OS notification) */
+        MODAL               = 0x10000000U,
+
+        /** Do not print contents of message to debug log */
+        SECURE              = 0x40000000U,
+
+        /** Predefined combinations for certain default usage cases */
+        MSG_INFORMATION = ICON_INFORMATION,
+        MSG_WARNING = (ICON_WARNING | BTN_OK | MODAL),
+        MSG_ERROR = (ICON_ERROR | BTN_OK | MODAL)
+    };
+
+#define ADD_SIGNALS_DECL_WRAPPER(signal_name, rtype, ...)                                  \
+    rtype signal_name(__VA_ARGS__);                                                        \
+    using signal_name##Sig = rtype(__VA_ARGS__);                                           \
+    boost::signals2::connection signal_name##_connect(std::function<signal_name##Sig> fn);
+
+    /** Show message box. */
+    ADD_SIGNALS_DECL_WRAPPER(ThreadSafeMessageBox, bool, const bilingual_str& message, const std::string& caption, unsigned int style);
+
+    /** If possible, ask the user a question. If not, falls back to ThreadSafeMessageBox(noninteractive_message, caption, style) and returns false. */
+    ADD_SIGNALS_DECL_WRAPPER(ThreadSafeQuestion, bool, const bilingual_str& message, const std::string& noninteractive_message, const std::string& caption, unsigned int style);
+
+    /** Progress message during initialization. */
+    ADD_SIGNALS_DECL_WRAPPER(InitMessage, void, const std::string& message);
+
+    /** Number of network connections changed. */
+    ADD_SIGNALS_DECL_WRAPPER(NotifyNumConnectionsChanged, void, int newNumConnections);
+
+    /** Network activity state changed. */
+    ADD_SIGNALS_DECL_WRAPPER(NotifyNetworkActiveChanged, void, bool networkActive);
+
+    /**
+     * Status bar alerts changed.
+     */
+    ADD_SIGNALS_DECL_WRAPPER(NotifyAlertChanged, void, );
+
+    /**
+     * Show progress e.g. for verifychain.
+     * resume_possible indicates shutting down now will result in the current progress action resuming upon restart.
+     */
+    ADD_SIGNALS_DECL_WRAPPER(ShowProgress, void, const std::string& title, int nProgress, bool resume_possible);
+
+    /** New block has been accepted */
+    ADD_SIGNALS_DECL_WRAPPER(NotifyBlockTip, void, SynchronizationState, const CBlockIndex*);
+
+    /** Best header has changed */
+    ADD_SIGNALS_DECL_WRAPPER(NotifyHeaderTip, void, SynchronizationState, const CBlockIndex*);
+
+    /** Banlist did change. */
+    ADD_SIGNALS_DECL_WRAPPER(BannedListChanged, void, void);
+};
+
+/** Show warning message **/
+void InitWarning(const bilingual_str& str);
+
+/** Show error message **/
+bool InitError(const bilingual_str& str);
+constexpr auto AbortError = InitError;
+
+extern CClientUIInterface uiInterface;
+
+#endif // BITCOIN_NODE_UI_INTERFACE_H