diff --git a/build_sysroot/Cargo.lock b/build_sysroot/Cargo.lock
index a2b8f449f00..990557694ea 100644
--- a/build_sysroot/Cargo.lock
+++ b/build_sysroot/Cargo.lock
@@ -47,9 +47,9 @@ checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
 [[package]]
 name = "cc"
-version = "1.0.65"
+version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "95752358c8f7552394baf48cd82695b345628ad3f170d607de3ca03b8dacca15"
+checksum = "4c0496836a84f8d0495758516b8621a622beb77c0fed418570e50764093ced48"
 
 [[package]]
 name = "cfg-if"
@@ -141,9 +141,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.80"
+version = "0.2.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4d58d1b70b004888f764dfbf6a26a3b0342a1632d33968e4a179d8011c760614"
+checksum = "1482821306169ec4d07f6aca392a4681f66c75c9918aa49641a2595db64053cb"
 dependencies = [
  "rustc-std-workspace-core",
 ]
diff --git a/build_sysroot/Cargo.toml b/build_sysroot/Cargo.toml
index e562dedb532..3dbd28c286a 100644
--- a/build_sysroot/Cargo.toml
+++ b/build_sysroot/Cargo.toml
@@ -5,13 +5,14 @@ version = "0.0.0"
 
 [dependencies]
 core = { path = "./sysroot_src/library/core" }
-compiler_builtins = "0.1"
 alloc = { path = "./sysroot_src/library/alloc" }
 std = { path = "./sysroot_src/library/std", features = ["panic_unwind", "backtrace"] }
 test = { path = "./sysroot_src/library/test" }
 
 alloc_system = { path = "./alloc_system" }
 
+compiler_builtins = { version = "=0.1.36", default-features = false }
+
 [patch.crates-io]
 rustc-std-workspace-core = { path = "./sysroot_src/library/rustc-std-workspace-core" }
 rustc-std-workspace-alloc = { path = "./sysroot_src/library/rustc-std-workspace-alloc" }
diff --git a/rust-toolchain b/rust-toolchain
index 547f1e0d8f0..eeee23d6a8b 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2020-12-03
+nightly-2020-12-17