devel/qbe: update to version 1.1

QBE 1.1 comes with improvements of performance and expressiveness.
Notable additions are:

• support for Apple ARM-based hardware (arm64_apple target);
• support for thread-local storage;
• a new blit instruction to copy small aggregates;
• a new hlt instruction to flag non-termination;
• a new stack slot coalescing optimization.