elfrc is a program which can turn arbitrary files into ELF object files which can then be linked into your program directly and accessed via simple, user-defined symbol names. Since this is much more effective than turning a binary file into a C array and then compiling that, it's possible to embed even huge (a few hundred megabytes) files directly into the executable and then access the data in constant time without making the compiler or linker eat loads of memory.
The CRT X-Y Library (libcrtxy) allows you to write vector-based video games (like Asteroids, Lunar Lander, and Battlezone from the 1970s and 80s). The end-user (and/or packager of your software) determines how lines are rendered, depending on the capabilities of their system. This choice includes anti-aliasing, alpha blending, blurring, and even the display size and depth. Fixed-point math is used, and sine and cosine trigonometric functions (using look-up tables) are provided. The library is based on libSDL and uses SDL as the video backend.