fixed gcc compile issues

app/audio/outputdeviceproxy.cpp

@@ -83,12 +83,15 @@ qint64 AudioOutputDeviceProxy::readData(char *data, qint64 maxlen)
 
 qint64 AudioOutputDeviceProxy::writeData(const char *data, qint64 maxSize)
 {
+  Q_UNUSED(data)
+  Q_UNUSED(maxSize)
+
   return -1;
 }
 
 qint64 AudioOutputDeviceProxy::ReverseAwareRead(char *data, qint64 maxlen)
 {
-  qint64 new_pos;
+  qint64 new_pos = -1;
 
   if (playback_speed_ < 0) {
     // If we're reversing, we'll seek back by maxlen bytes before we read

app/audio/outputmanager.h

@@ -21,6 +21,7 @@
 #ifndef AUDIOHYBRIDDEVICE_H
 #define AUDIOHYBRIDDEVICE_H
 
+#include <memory>
 #include <QAudioOutput>
 #include <QBuffer>
 #include <QIODevice>

app/audio/tempoprocessor.cpp

@@ -162,7 +162,7 @@ void TempoProcessor::Push(const char *data, int length)
     }
 
     // Copy buffer from data array to frame
-    memcpy(src_frame->data[0], data, length);
+    memcpy(src_frame->data[0], data, static_cast<size_t>(length));
   }
 
   int ret = av_buffersrc_add_frame_flags(buffersrc_ctx_, src_frame, AV_BUFFERSRC_FLAG_KEEP_REF);
@@ -204,7 +204,7 @@ int TempoProcessor::Pull(char *data, int max_length)
   int copy_length = qMin(max_length, processed_frame_max_bytes_ - processed_frame_byte_index_);
 
   // Copy the bytes
-  memcpy(data, processed_frame_->data[0] + processed_frame_byte_index_, copy_length);
+  memcpy(data, processed_frame_->data[0] + processed_frame_byte_index_, static_cast<size_t>(copy_length));
 
   // Add the copied amount to the current index
   processed_frame_byte_index_ += copy_length;