Fixed msys2 build crash

src/util.cpp

@@ -225,7 +225,7 @@ void uv_rwlock_init_checked(uv_rwlock_t* lock)
 
 uv_loop_t* uv_default_loop_checked()
 {
-	if (!is_main_thread) {
+	if (!is_main_thread()) {
 		LOGERR(1, "uv_default_loop() can only be used by the main thread. Fix the code!");
 #ifdef _WIN32
 		if (IsDebuggerPresent()) {
@@ -339,7 +339,10 @@ void BackgroundJobTracker::print_status()
 }
 
 BackgroundJobTracker bkg_jobs_tracker;
-thread_local bool is_main_thread = false;
+
+static thread_local bool main_thread = false;
+void set_main_thread() { main_thread = true; }
+bool is_main_thread() { return main_thread; }
 
 bool resolve_host(std::string& host, bool& is_v6)
 {