Exactly. Extend it with what? Intel and AMD each have instructions in their x86 chips that the other doesn't have. No one cares, pretty much. If you're buildin

Exactly. Extend it with what? Intel and AMD each have instructions in their x86 chips that the other doesn't have. No one cares, pretty much. If you're building your own performance-critical software to run on a specific chip then you might enable some of them (or just do "gcc -march=native") but software distributed in binary form generally gets on fine without them.