peepmatic: Introduce the main peepmatic crate

Peepmatic is a DSL for peephole optimizations and compiler for generating
peephole optimizers from them. The user writes a set of optimizations in the
DSL, and then `peepmatic` compiles the set of optimizations into an efficient
peephole optimizer:

```
DSL ----peepmatic----> Peephole Optimizer
```

The generated peephole optimizer has all of its optimizations' left-hand sides
collapsed into a compact automata that makes matching candidate instruction
sequences fast.

The DSL's optimizations may be written by hand or discovered mechanically with a
superoptimizer like [Souper][]. Eventually, `peepmatic` should have a verifier
that ensures that the DSL's optimizations are sound, similar to what [Alive][]
does for LLVM optimizations.

[Souper]: https://github.com/google/souper
[Alive]: https://github.com/AliveToolkit/alive2

cranelift/peepmatic/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "peepmatic"
+version = "0.1.0"
+authors = ["Nick Fitzgerald <fitzgen@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow = "1.0.27"
+peepmatic-automata = { version = "0.1.0", path = "crates/automata", features = ["dot"] }
+peepmatic-macro = { version = "0.1.0", path = "crates/macro" }
+peepmatic-runtime = { version = "0.1.0", path = "crates/runtime", features = ["construct"] }
+wast = "13.0.0"
+z3 = { version = "0.5.0", features = ["static-link-z3"] }