[All] Fixed multiple issues during build on Linux

- Added some fixes introduced by RodoMa92 in PR198

- Lack of AVX2 extension (should be done differently in the future)
- Disable deprecated-volatile warning
- Added missing override in posix EventInfo, ImGui notification class and XContent class
- Removed not used XAudio2.h include in XMP
- Fixed missing switch-case in XObject
- Added fugly template in native_list.h
- Fixed multiple smaller issues

src/xenia/gpu/draw_util.cc

@@ -580,10 +580,17 @@ static inline void GetScissorTmpl(const RegisterFile& XE_RESTRICT regs,
   __m128i pa_sc_scissor = _mm_setr_epi32(
       pa_sc_screen_scissor_tl_tl_x, pa_sc_screen_scissor_tl_tl_y,
       pa_sc_screen_scissor_br_br_x, pa_sc_screen_scissor_br_br_y);
+#if XE_PLATFORM_WIN32
   __m128i xyoffsetadd = _mm_cvtsi64x_si128(
       static_cast<unsigned long long>(pa_sc_window_offset_window_x_offset) |
       (static_cast<unsigned long long>(pa_sc_window_offset_window_y_offset)
        << 32));
+#else
+  __m128i xyoffsetadd = _mm_cvtsi64_si128(
+      static_cast<unsigned long long>(pa_sc_window_offset_window_x_offset) |
+      (static_cast<unsigned long long>(pa_sc_window_offset_window_y_offset)
+       << 32));
+#endif
   xyoffsetadd = _mm_unpacklo_epi64(xyoffsetadd, xyoffsetadd);
   // chrispy: put this here to make it clear that the shift by 31 is extracting
   // this field