I was working on a math library for C for a while and I want to let OpenGL community know about its existence.

It is called cglm here the link: http://github.com/recp/cglm
It is similar to original glm library but for C.

Most vec4/mat4 functions are optimized with SIMD (SSE, AVX, Neon ...) instructions and some of them also optimized manually. There are inline and non-inline versions of functions. I'm trying to add convenient functions for some common problems. You can see full feature list in README. It is in active development and some features may be added by time.

Quaternion part may need to be updated later. It stores quat as [w x y z] this may change to [ x y z w] later (I'm not sure) and more features will be added by time.

Also any feedbacks are welcome (always).