Total hack. Simply disable m_mailbox, to allow for GCC 4.6 compat.

util/Mailbox.h and util/FunctorIterator.h use template aliases, which
are not supported until GCC 4.7. Just kill off m_mailbox for now, and
maybe consider another solution later.

OMXPlayerSubtitles.cpp

@@ -83,7 +83,9 @@ bool OMXPlayerSubtitles::Open(size_t stream_count,
   if(!Create())
     return false;
 
+#if 0
   m_mailbox.send(Message::Flush{m_external_subtitles});
+#endif
 
 #ifndef NDEBUG
   m_open = true;
@@ -96,11 +98,15 @@ void OMXPlayerSubtitles::Close() BOOST_NOEXCEPT
 {
   if(Running())
   {
+#if 0
     m_mailbox.send(Message::Stop{});
+#endif
     StopThread();
   }
 
+#if 0
   m_mailbox.clear();
+#endif
   m_subtitle_buffers.clear();
 
 #ifndef NDEBUG
@@ -222,6 +228,7 @@ RenderLoop(const string& font_path,
                       0, 1000);
     }
 
+#if 0
     m_mailbox.receive_wait(chrono::milliseconds(timeout),
       [&](Message::Push&& args)
       {
@@ -249,6 +256,7 @@ RenderLoop(const string& font_path,
       {
         exit = true;
       });
+#endif
 
     if(exit) break;
 
@@ -296,15 +304,19 @@ void OMXPlayerSubtitles::FlushRenderer()
 
   if(GetUseExternalSubtitles())
   {
+#if 0
     m_mailbox.send(Message::Flush{m_external_subtitles});
+#endif
   }
   else
   {
     Message::Flush flush;
     assert(!m_subtitle_buffers.empty());
     for(auto& s : m_subtitle_buffers[m_active_index])
       flush.subtitles.push_back(s);
+#if 0
     m_mailbox.send(move(flush));
+#endif
   }
 }
 
@@ -317,10 +329,12 @@ void OMXPlayerSubtitles::Flush(double pts) BOOST_NOEXCEPT
 
   if(GetVisible())
   {
+#if 0
     if(GetUseExternalSubtitles())
       m_mailbox.send(Message::Seek{static_cast<int>(pts/1000)});
     else
       m_mailbox.send(Message::Flush{});
+#endif
   }
 }
 
@@ -329,15 +343,19 @@ void OMXPlayerSubtitles::Resume() BOOST_NOEXCEPT
   assert(m_open);
 
   m_paused = false;
+#if 0
   m_mailbox.send(Message::SetPaused{false});
+#endif
 }
 
 void OMXPlayerSubtitles::Pause() BOOST_NOEXCEPT
 {
   assert(m_open);
 
   m_paused = true;
+#if 0
   m_mailbox.send(Message::SetPaused{true});
+#endif
 }
 
 void OMXPlayerSubtitles::SetUseExternalSubtitles(bool use) BOOST_NOEXCEPT
@@ -355,7 +373,9 @@ void OMXPlayerSubtitles::SetDelay(int value) BOOST_NOEXCEPT
   assert(m_open);
 
   m_delay = value;
+#if 0
   m_mailbox.send(Message::SetDelay{value});
+#endif
 }
 
 void OMXPlayerSubtitles::SetVisible(bool visible) BOOST_NOEXCEPT
@@ -375,7 +395,9 @@ void OMXPlayerSubtitles::SetVisible(bool visible) BOOST_NOEXCEPT
     if(m_visible)
     {
       m_visible = false;
+#if 0
       m_mailbox.send(Message::Flush{});
+#endif
     }
   }
 }
@@ -436,11 +458,13 @@ bool OMXPlayerSubtitles::AddPacket(OMXPacket *pkt, size_t stream_index) BOOST_NO
     return true;
   }
 
+#if 0
   if(pkt->hints.codec != AV_CODEC_ID_SUBRIP && 
      pkt->hints.codec != AV_CODEC_ID_SSA)
   {
     return true;
   }
+#endif
 
   auto start = static_cast<int>(pkt->pts/1000);
   auto stop = start + static_cast<int>(pkt->duration/1000);
@@ -460,7 +484,9 @@ bool OMXPlayerSubtitles::AddPacket(OMXPacket *pkt, size_t stream_index) BOOST_NO
      GetVisible() &&
      stream_index == GetActiveStream())
   {
+#if 0
     m_mailbox.send(Message::Push{{start, stop, move(text_lines)}});
+#endif
   }
 
   return true;

OMXPlayerSubtitles.h

@@ -23,7 +23,7 @@
 #include "OMXClock.h"
 #include "OMXOverlayCodecText.h"
 #include "Subtitle.h"
-#include "utils/Mailbox.h"
+//#include "utils/Mailbox.h"
 
 #include <boost/config.hpp>
 #include <boost/circular_buffer.hpp>
@@ -122,12 +122,14 @@ class OMXPlayerSubtitles : public OMXThread
   COMXOverlayCodecText                          m_subtitle_codec;
   std::vector<Subtitle>                         m_external_subtitles;
   std::vector<boost::circular_buffer<Subtitle>> m_subtitle_buffers;
+#if 0
   Mailbox<Message::Stop,
           Message::Flush,
           Message::Push,
           Message::Seek,
           Message::SetPaused,
           Message::SetDelay>                    m_mailbox;
+#endif
   bool                                          m_paused;
   bool                                          m_visible;
   bool                                          m_use_external_subtitles;