Docs: steps to build aria2

Author: xibr

README.md

@@ -156,6 +156,7 @@ request.addOption("--external-downloader-args", "aria2c:\"--summary-interval=1\"
 
 *  Though not required for just using this library, documentation on building python for android can be seen [here](BUILD_PYTHON.md). Same for ffmpeg [here](BUILD_FFMPEG.md). Alternatively, you can use pre-built packages from [here (android5+)](https://packages.termux.dev/apt/termux-main-21/pool/main/) or [here (android7+)](https://packages.termux.dev/apt/termux-main/pool/main/).
 * youtubedl-android uses lazy extractors based build of yt-dlp - [ytdlp-lazy](https://github.com/xibr/ytdlp-lazy) (formerly [youtubedl-lazy](https://github.com/yausername/youtubedl-lazy/))
+* To build `aria2` you need `libc++, c-ares, openssl, libxml2, zlib, ibiconv` it can be found in [here (android5+)](https://packages.termux.dev/apt/termux-main-21/pool/main/) or [here (android7+)](https://packages.termux.dev/apt/termux-main/pool/main/). then follow the method used to build [python](BUILD_PYTHON.md) or [ffmpeg](BUILD_FFMPEG.md).
 
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