MAME is a multi-purpose emulation framework
Cross platform toolkit for creative coding in C++
Source code is here - https://sourceforge.net/projects/lcmd-git/
Keystone assembler framework: Core (Arm, Arm64, Hexagon, Mips, etc.)
A cross-platform game library based on XNA, but written in C++
The official mirror of the V8 Git repository
Utility classes for the Wt C++/JavaScript web framework