Racket (formerly PLT Scheme) is a programming language suitable for implementation tasks ranging from scripting to application development, including GUIs, Web services, etc. It includes the DrRacket programming environment, a virtual machine with a just-in-time compiler, tools for creating stand-alone executables, the Racket Web server, extensive libraries, documentation for both beginners and experts, and more. It supports the creation of new programming languages through a rich, expressive syntax system. Example languages include Typed Racket, ACL2, FrTime, and Lazy Racket.
crosstool-NG is a versatile toolchain generator, aiming at being highly configurable. It supports multiple target architectures, different components (glibc/uClibc...) and versions. crosstool-NG also features debugging utilities (DUMA, strace...) and generation tools (sstrip...).
coNCePTuaL is a domain-specific programming language for rapidly generating programs that measure the performance and/or test the correctness of networks and network protocol layers. A few lines of coNCePTuaL code can produce programs that would take significantly more effort to write in a conventional programming language.
The pl1gcc project is an attempt to create a native PL/I compiler using the GNU Compiler Collection. PL/I is a third-generation procedural language suitable for a wide range of applications including system software, graphics, simulation, text processing, Web, and business applications.