Fixes for 0.15 (#1449)

* Wasmtime 0.15.0 and Cranelift 0.62.0. (#1398)

* Bump more ad-hoc versions.

* Add build.rs to wasi-common's Cargo.toml.

* Update the env var name in more places.

* Remove a redundant echo.

crates/debug/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "wasmtime-debug"
-version = "0.14.0"
+version = "0.15.0"
 authors = ["The Wasmtime Project Developers"]
 description = "Debug utils for WebAsssembly code in Cranelift"
 license = "Apache-2.0 WITH LLVM-exception"
@@ -15,7 +15,7 @@ edition = "2018"
 gimli = "0.20.0"
 wasmparser = "0.51.2"
 faerie = "0.15.0"
-wasmtime-environ = { path = "../environ", version = "0.14.0" }
+wasmtime-environ = { path = "../environ", version = "0.15.0" }
 target-lexicon = { version = "0.10.0", default-features = false }
 anyhow = "1.0"
 thiserror = "1.0.4"