[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.h

@@ -100,7 +100,7 @@ constexpr bool IsPrimitivePolygonal(bool vgt_output_path_is_tessellation_enable,
   return (primitive_polygonal_table & (1U << static_cast<uint32_t>(type))) != 0;
 }
 XE_FORCEINLINE
-bool IsPrimitivePolygonal(const RegisterFile& regs) {
+static bool IsPrimitivePolygonal(const RegisterFile& regs) {
   return IsPrimitivePolygonal(
       regs.Get<reg::VGT_OUTPUT_PATH_CNTL>().path_select ==
           xenos::VGTOutputPath::kTessellationEnable,