Update check-cfg lists for alloc

Author: tesuji

library/alloc/Cargo.toml

@@ -38,3 +38,12 @@ compiler-builtins-mangled-names = ["compiler_builtins/mangled-names"]
 compiler-builtins-weak-intrinsics = ["compiler_builtins/weak-intrinsics"]
 # Make panics and failed asserts immediately abort without formatting any message
 panic_immediate_abort = []
+
+[lints.rust.unexpected_cfgs]
+level = "warn"
+check-cfg = [
+    'cfg(no_global_oom_handling)',
+    'cfg(bootstrap)',
+    'cfg(no_rc)',
+    'cfg(no_sync)',
+]