Better user programs with a special std. Sleep and exit are calling scheduler instead of wfi.

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 resolver = "3"
-members = ["user/*"]
+members = ["crates/os-std", "crates/shared", "user/*"]
 
 [package]
 name = "kernel-rust"
@@ -13,3 +13,4 @@ kernel-macros = { path = "crates/kernel-macros" }
 log = "0.4"
 critical-section = { version = "1", features = ["restore-state-bool"] }
 bffs = { path = "../../../code/bffs", features = ["alloc"] }
+shared = { path = "crates/shared" }