Add a special exception logger

We'll need this to make sure that we can redirect caught exceptions
printed in `src/common/` to the correct file if `YABRIDGE_DEBUG_FILE` is
set.

src/common/logging/common.cpp

@@ -116,6 +116,14 @@ Logger Logger::create_wine_stderr() {
         "", std::shared_ptr<std::ostream>(&std::cerr, [](auto*) {}), false);
 }
 
+Logger Logger::create_exception_logger() {
+#ifdef __WINE__
+    return Logger::create_wine_stderr();
+#else
+    return Logger::create_from_environment("[error] ");
+#endif
+}
+
 void Logger::log(const std::string& message) {
     std::ostringstream formatted_message;
 

src/common/logging/common.h

@@ -137,6 +137,17 @@ class Logger {
      */
     static Logger create_wine_stderr();
 
+    /**
+     * Create a special logger instance for printing caught exceptions. This
+     * simply calls `Logger::create_from_environment()` on the plugin side, and
+     * `Logger::create_wine_stderr()` on the Wine side. Printing directly to
+     * STDERR on the Wine side is fine, but on the plugin side that means that
+     * we cannot redirect the output with `YABRIDGE_DEBUG_FILE`. So this should
+     * also be used instead of writing to `std::cerr` when catching exceptions
+     * in `src/common/`.
+     */
+    static Logger create_exception_logger();
+
     /**
      * Write a message to the log, prefixing it with a timestamp and this
      * logger's prefix string.

src/plugin/vst2-plugin.cpp

@@ -50,7 +50,7 @@ extern "C" VST_EXPORT AEffect* VSTPluginMain(
 
         return &bridge->plugin;
     } catch (const std::exception& error) {
-        Logger logger = Logger::create_from_environment();
+        Logger logger = Logger::create_exception_logger();
         logger.log("Error during initialization:");
         logger.log(error.what());
 

src/plugin/vst3-plugin.cpp

@@ -53,7 +53,7 @@ bool InitModule() {
 
         return true;
     } catch (const std::exception& error) {
-        Logger logger = Logger::create_from_environment();
+        Logger logger = Logger::create_exception_logger();
         logger.log("Error during initialization:");
         logger.log(error.what());