The AUX compiler supports several languages: Ada, C, C++, Fortran and
Objective-C.  Since Ada support must be built by an Ada-capable compiler,
only platforms for which a bootstrap compiler is available can build the
AUX compiler.

The AUX compiler is based on release versions of the Free Software
Foundation's GNU Compiler Collection.  It carries with it the GMGPL license,
the modified version of the GPL that exempts generic instantiation from
resulting in a GPL-licensed executable.  It also carries the GCC Runtime
Library Exception, so the resulting binaries have no licensing requirements.
Binaries produced by the AUX compiler should be legally handled the same as
binaries produced by any FSF compiler.

The AUX GNAT compiler the full Ada-83, Ada-95, Ada-2005 standard and
provides a partial implementation of Ada-2012.  The Ada-2012 reference manual
was submitted to the International Organization for Standardization (ISO)
in June 2012.