Merge pull request #12 from alexcrichton/update-support

Update support for being built in rust-lang/rust

Author: alexcrichton

Cargo.toml

@@ -17,7 +17,13 @@ according to Unicode Standard Annex #11 rules.
 
 exclude = [ "target/*", "Cargo.lock" ]
 
+[dependencies]
+std = { version = "1.0", package = "rustc-std-workspace-std", optional = true }
+core = { version = "1.0", package = "rustc-std-workspace-core", optional = true }
+compiler_builtins = { version = "0.1", optional = true }
+
 [features]
 default = []
 no_std = []
 bench = []
+rustc-dep-of-std = ['std', 'core', 'compiler_builtins']