Cargo.toml: Update release profile, add releaselto

- `release` should use `panic=abort` by default because we make
  heavy use of FFI and this is safest, and I don't think we need
  unwinding anyways
- The `releaselto` produces smallest binaries

Signed-off-by: Colin Walters <walters@verbum.org>

Cargo.toml

@@ -5,9 +5,17 @@ members = ["cli", "lib", "xtask"]
 opt-level = 1 # No optimizations are too slow for us.
 
 [profile.release]
-# RPMs/debs/etc want debuginfo by default
+lto = "thin"
+# We use FFI so this is safest
+panic = "abort"
+# We assume we're being delivered via e.g. RPM which supports split debuginfo
 debug = true
 
+[profile.releaselto]
+codegen-units = 1
+inherits = "release"
+lto = "yes"
+
 # See https://github.com/coreos/cargo-vendor-filterer
 [workspace.metadata.vendor-filter]
 # For now we only care about tier 1+2 Linux.  (In practice, it's unlikely there is a tier3-only Linux dependency)