treewide: explicity load built-in rules

In Bazel 9 all autoloaded rules will be disabled. This prepares us for
that.

Change-Id: Ibaa4fa2e6b7095922a5699d2d5f3ae6c2cba3552
Reviewed-on: https://review.monogon.dev/c/monogon/+/3939
Tested-by: Jenkins CI
Reviewed-by: Leopold Schabel <leo@monogon.tech>
diff --git a/build/toolchain/llvm-efi/BUILD.bazel b/build/toolchain/llvm-efi/BUILD.bazel
index 9bce651..169a37f 100644
--- a/build/toolchain/llvm-efi/BUILD.bazel
+++ b/build/toolchain/llvm-efi/BUILD.bazel
@@ -1,3 +1,4 @@
+load("@rules_cc//cc:defs.bzl", "cc_toolchain")
 load(":cc_toolchain_config.bzl", "efi_k8_cc_toolchain_config")
 
 package(default_visibility = ["//visibility:public"])