BSD 4.3 still used the Portable C Compiler. By 4.4 Berkeley was starting to use GCC, but that wasn't available in time to incorporate into A/UX. Plus, IIRC the

BSD 4.3 still used the Portable C Compiler. By 4.4 Berkeley was starting to use GCC, but that wasn't available in time to incorporate into A/UX. Plus, IIRC the GNU project was actively boycotting Apple at the time, and so Apple was probably adverse to incorporating any GNU software.