Use build-std-features instead of rlibc

.cargo/config

@@ -1,2 +1,3 @@
 [unstable]
 build-std = ["core", "compiler_builtins", "alloc"]
+build-std-features = ["compiler-builtins-mem"]

BUILDING.md

@@ -22,9 +22,8 @@ application. Copy it to a new directory to get started.
 
 ## Building and running
 
-- Build using a `nightly` version of the compiler and activate the
-  [`build-std`](https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#build-std)
-  Cargo feature: `cargo +nightly build -Z build-std --target x86_64-unknown-uefi`.
+- Build using a `nightly` version of the compiler:
+  `cargo +nightly build --target x86_64-unknown-uefi`.
 
 - The `target` directory will contain a `x86_64-unknown-uefi` subdirectory,
   where you will find the `uefi_app.efi` file - a normal UEFI executable.

template/.cargo/config

@@ -1,2 +1,3 @@
 [unstable]
 build-std = ["core", "compiler_builtins", "alloc"]
+build-std-features = ["compiler-builtins-mem"]

template/Cargo.toml

@@ -4,8 +4,6 @@ version = "0.1.0"
 edition = "2018"
 
 [dependencies]
-rlibc = "1.0.0"
-
 # In a real application, change these to point to the latest release
 # on crates.io.
 uefi = { path = "..", features = ["exts"] }

template/src/main.rs

@@ -2,8 +2,6 @@
 #![no_std]
 #![feature(abi_efiapi)]
 
-extern crate rlibc;
-
 use uefi::prelude::*;
 use uefi::ResultExt;
 

uefi-test-runner/Cargo.toml

@@ -11,10 +11,6 @@ uefi-services = { path = "../uefi-services" }
 
 log = { version = "0.4.11", default-features = false }
 
-# When building using Cargo's `build-std` feature, the `mem` feature of `compiler-builtins`
-# does not automatically get enabled. Therefore, we have to manually add support for
-# the memory functions.
-rlibc = "1.0.0"
 qemu-exit = "2.0.0"
 
 [features]

uefi-test-runner/src/main.rs

@@ -8,9 +8,6 @@ extern crate log;
 #[macro_use]
 extern crate alloc;
 
-// Keep this line to ensure the `mem*` functions are linked in.
-extern crate rlibc;
-
 use alloc::string::String;
 use core::mem;
 use uefi::prelude::*;