Fix minor code issues

ext/libstrawberry-tagreader/CMakeLists.txt

@@ -9,6 +9,10 @@ set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --std=c++11 -U__STRICT_ANSI__ -Wall -Woverloaded-virtual -Wno-sign-compare -fpermissive")
 
+if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wextra -Wimplicit-fallthrough=0 -Wpedantic")
+endif()
+
 set(MESSAGES
   tagreadermessages.proto
 )

ext/libstrawberry-tagreader/tagreader.cpp

@@ -478,6 +478,8 @@ void TagReader::ParseOggTag(const TagLib::Ogg::FieldListMap &map, const QTextCod
 
 void TagReader::ParseAPETag(const TagLib::APE::ItemListMap &map, const QTextCodec *codec, QString *disc, QString *compilation, pb::tagreader::SongMetadata *song) const {
 
+  Q_UNUSED(codec);
+
   TagLib::APE::ItemListMap::ConstIterator it = map.find("ALBUM ARTIST");
   if (it != map.end()) {
     TagLib::StringList album_artists = it->second.toStringList();