turn off aggressive optimizations

In Rust 1.72, too many things are breaking when default optimizations
are turned on, and I don't have the time to figure out what is breaking.

But issue #416 makes me think that the issue isn't our code, it's
something in llvm.

Cargo.toml

@@ -123,7 +123,7 @@ strip = false
 lto = "fat"
 incremental = true
 #panic = "abort" # Remove panic output, which can reduce file size
-#opt-level = 1  # z,s: Optimize for size instead of performance; 1 for easier debugging
+opt-level = "s"  # z,s: Optimize for size instead of performance; 1 for easier debugging; comment out for "best performance" (but in Rust 1.72 this causes regressions)
 
 # prefer hardware-accelerated versions of services
 [patch.crates-io.sha2]