GNU Common Lisp
GNU Common Lisp is the GNU Project's ANSI Common Lisp compiler, an evolutionary development of Kyoto Common Lisp. It produces native object code by first generating C code and then calling a C compiler.
GCL is the implementation of choice for several large projects including the mathematical tools Maxima, AXIOM, HOL88, and ACL2. GCL runs under eleven different architectures on Linux, and under FreeBSD, Solaris, Mac OS X, and Microsoft Windows.
GCL remains under active development, with stable releases as of 2014-10-28. Prerelease development can be followed using the git revision control system.