To JIT (or not!) in Ubuntu packages

[Ben Chobot]

We've noticed that the Ubuntu postgresql-12 package has --with-llvm 
enabled on x86_64, but not on aarch64. Does anybody know if this was 
intentional, or just an oversight?

For what it's worth, it seems the beta postgresql-14 package for Ubuntu 
still doesn't have --with-llvm.

I'm not sure if this explains why our aarch64 DBs are missing a 
jit_provider GUC variable, but I expect it does explain why 
pg_jit_available() tells me no.