refactor: Make TraceThread a non-template free function

Also it is moved into its own module.

src/util/system.h

@@ -22,7 +22,6 @@
 #include <sync.h>
 #include <tinyformat.h>
 #include <util/settings.h>
-#include <util/threadnames.h>
 #include <util/time.h>
 
 #include <any>
@@ -458,28 +457,6 @@ std::string HelpMessageOpt(const std::string& option, const std::string& message
  */
 int GetNumCores();
 
-/**
- * .. and a wrapper that just calls func once
- */
-template <typename Callable> void TraceThread(const char* name,  Callable func)
-{
-    util::ThreadRename(name);
-    try
-    {
-        LogPrintf("%s thread start\n", name);
-        func();
-        LogPrintf("%s thread exit\n", name);
-    }
-    catch (const std::exception& e) {
-        PrintExceptionContinue(&e, name);
-        throw;
-    }
-    catch (...) {
-        PrintExceptionContinue(nullptr, name);
-        throw;
-    }
-}
-
 std::string CopyrightHolders(const std::string& strPrefix);
 
 /**

src/util/thread.cpp

@@ -0,0 +1,27 @@
+// Copyright (c) 2021 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 <util/thread.h>
+
+#include <logging.h>
+#include <util/system.h>
+#include <util/threadnames.h>
+
+#include <exception>
+
+void util::TraceThread(const char* thread_name, std::function<void()> thread_func)
+{
+    util::ThreadRename(thread_name);
+    try {
+        LogPrintf("%s thread start\n", thread_name);
+        thread_func();
+        LogPrintf("%s thread exit\n", thread_name);
+    } catch (const std::exception& e) {
+        PrintExceptionContinue(&e, thread_name);
+        throw;
+    } catch (...) {
+        PrintExceptionContinue(nullptr, thread_name);
+        throw;
+    }
+}

src/util/thread.h

@@ -0,0 +1,18 @@
+// Copyright (c) 2021 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_UTIL_THREAD_H
+#define BITCOIN_UTIL_THREAD_H
+
+#include <functional>
+
+namespace util {
+/**
+ * A wrapper for do-something-once thread functions.
+ */
+void TraceThread(const char* thread_name, std::function<void()> thread_func);
+
+} // namespace util
+
+#endif // BITCOIN_UTIL_THREAD_H