Supporting changes for CFI toolchain features

Mostly exporting variables to Bazel, but also allowlisting a BUILD
file.

Bug: 251217226
Test: Unit tests
Change-Id: Id87015a3cd5d970700c4058ec989bb0c14c36bcb
diff --git a/tests/lib.sh b/tests/lib.sh
index 2bcb630..26608b8 100644
--- a/tests/lib.sh
+++ b/tests/lib.sh
@@ -91,6 +91,7 @@
   symlink_directory prebuilts/go
   symlink_directory prebuilts/build-tools
   symlink_directory prebuilts/clang/host
+  symlink_directory external/compiler-rt
   symlink_directory external/go-cmp
   symlink_directory external/golang-protobuf
   symlink_directory external/starlark-go