Fix compilation with MinGW on Windows

Use the explicit 'W' (wide) symbols from the Windows API to provide
Unicode support regardless of whether UNICODE is defined:

- SetFileAttributesW
- LPCWSTR

Define UNICODE anyway for the sake of thirdparty code that uses the
aliases, which only work properly when UNICODE is defined:

- SetFileAttributes
- LPCTSTR

If UNICODE is not defined then the aliases refer to the narrow symbols:

- SetFileAttributesA
- LPCSTR

But the explict 'W' symbols are still available. The aliases are only
needed for compatibility with code written prior to Windows NT.

build/cmake/SetupBuildEnvironment.cmake

@@ -53,6 +53,9 @@ elseif(CC_IS_MINGW)
         set(CMAKE_EXE_LINKER_FLAGS "-Wl,--large-address-aware")
     endif (NOT BUILD_64)
 
+    add_definitions(-D_UNICODE)
+    add_definitions(-DUNICODE)
+
 elseif(CC_IS_CLANG)
     message(STATUS "Using Compiler CLANG ${CMAKE_CXX_COMPILER_VERSION}")
 

src/framework/ui/internal/platform/windows/windowsplatformtheme.cpp

@@ -75,9 +75,9 @@ void WindowsPlatformTheme::startListening()
         return;
     }
     m_isListening = true;
-    if (RegOpenKeyEx(HKEY_CURRENT_USER, windowsThemeKey.c_str(), 0,
-                     KEY_NOTIFY | KEY_CREATE_SUB_KEY | KEY_ENUMERATE_SUB_KEYS | KEY_QUERY_VALUE | KEY_WOW64_64KEY,
-                     &hKey) == ERROR_SUCCESS) {
+    if (RegOpenKeyExW(HKEY_CURRENT_USER, windowsThemeKey.c_str(), 0,
+                      KEY_NOTIFY | KEY_CREATE_SUB_KEY | KEY_ENUMERATE_SUB_KEYS | KEY_QUERY_VALUE | KEY_WOW64_64KEY,
+                      &hKey) == ERROR_SUCCESS) {
         m_listenThread = std::thread([this]() { th_listen(); });
     } else {
         LOGD() << "Failed opening key for listening dark theme changes.";

src/libmscore/scorefile.cpp

@@ -449,16 +449,7 @@ bool MasterScore::saveFile(bool generateBackup)
             dir.mkdir(backupSubdirString);
 #ifdef Q_OS_WIN
             const QString backupDirNativePath = QDir::toNativeSeparators(backupDirString);
-#if (defined (_MSCVER) || defined (_MSC_VER))
-   #if (defined (UNICODE))
-            SetFileAttributes((LPCTSTR)backupDirNativePath.unicode(), FILE_ATTRIBUTE_HIDDEN);
-   #else
-            // Use byte-based Windows function
-            SetFileAttributes((LPCTSTR)backupDirNativePath.toLocal8Bit(), FILE_ATTRIBUTE_HIDDEN);
-   #endif
-#else
-            SetFileAttributes((LPCTSTR)backupDirNativePath.toLocal8Bit(), FILE_ATTRIBUTE_HIDDEN);
-#endif
+            SetFileAttributesW(reinterpret_cast<LPCWSTR>(backupDirNativePath.utf16()), FILE_ATTRIBUTE_HIDDEN);
 #endif
         }
         const QString backupName = QString(".") + info.fileName() + QString(",");