JIT memory is now mapped with MAP_JIT, and pthread_jit_write_protect_np()
switches the calling thread's view of it, in place of two mprotect() calls
for every block compiled and every exit linked. This makes compiling
cheaper, which matters mostly in the first seconds after a game or state
loads. A hardened runtime without the JIT entitlement refuses the mapping,
and then it's mprotect() as before.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
