nicbarker/clay: High performance UI layout library in C.

Clay, a high performance 2D UI layout library in C, offers microsecond layout performance and a flex-box like model. It features zero dependencies, Wasm support, static arena-based memory usage, and a renderer-agnostic output. The library can compile to a 15kb uncompressed .wasm file for browser use, and it supports nested declarative syntax and various UI element macros like containers, text, images, and more. Additionally, it provides simple APIs for pointer interactions and scroll container handling. Clay was designed for immediate mode rendering but can also be integrated into retained mode systems using its API for visibility culling and custom elements.