libctru
Homebrew development library for Nintendo 3DS/Horizon OS user mode
...It is not meant to provide higher-level functions; to put things in perspective, the purpose of libctru would be to sit between the OS and a possible port of SDL rather than replace it. libctru is just a library and needs a toolchain to function. devkitARM (created by devkitPro) is the officially supported ARM cross-compiling toolchain, which provides the framework necessary to supply a usable POSIX-like environment, with working C and C++ standard libraries; as well as the tools required to compile homebrew in the 3DSX format, and assemble GPU shaders. The use of other ARM toolchains is severely discouraged.