Fix codebase in preparation for incompatible_use_cc_configure_from_rules_cc

We're working on removing C++ toolchain autoconfiguration logic out of Bazel,
and moving towards using rules_cc repository for it. Some bzl files will no
longer be available through bazel/tools/cpp/*, but through
@rules_cc/cc/*.

RELNOTES: None.
PiperOrigin-RevId: 279935457
Change-Id: I3bae259548dacc5c6789efe0f27dd07738c1057c
diff --git a/cc/private/rules_impl/cc_flags_supplier.bzl b/cc/private/rules_impl/cc_flags_supplier.bzl
index 103b3da..b0a64b5 100644
--- a/cc/private/rules_impl/cc_flags_supplier.bzl
+++ b/cc/private/rules_impl/cc_flags_supplier.bzl
@@ -28,8 +28,8 @@
 cc_flags_supplier = rule(
     implementation = _cc_flags_supplier_impl,
     attrs = {
-        "_cc_toolchain": attr.label(default = Label("@rules_cc//cc:current_cc_toolchain")),
+        "_cc_toolchain": attr.label(default = Label("@bazel_tools//tools/cpp:current_cc_toolchain")),
     },
-    toolchains = ["@rules_cc//cc:toolchain_type"],
+    toolchains = ["@bazel_tools//tools/cpp:toolchain_type"],
     fragments = ["cpp"],
 )