Extracted from here: https://github.com/telegramdesktop/tdesktop/tree/dev/Telegram/SourceFiles/codegen/emoji

1. Install qtbase5-dev
2. cd src && make
3. ./emoji_codegen ../emoji_autocomplete.json

This generates emoji_suggestions_data.{h,cpp} which is used by Telegram-Android. The other set of files emoji_suggestions.{h,cpp} comes from here: https://github.com/telegramdesktop/tdesktop/tree/dev/Telegram/ThirdParty/emoji_suggestions