bazel: Buildkite CI breakage:

A number of bazel downstream dependencies are broken in recent CI runs.

The breakages have some error message in common, for example:

https://buildkite.com/bazel/bazel-with-downstream-projects-bazel/builds/349#a31ac896-3769-483e-9876-81c55ddbe4ba

this rule is missing dependency declarations for the following files included by 'external/grpc/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.cc':
  '/usr/lib/gcc/x86_64-linux-gnu/7/include/stdint.h'
  '/usr/lib/gcc/x86_64-linux-gnu/7/include/stddef.h'
  '/usr/lib/gcc/x86_64-linux-gnu/7/include/stdarg.h'
  '/usr/lib/gcc/x86_64-linux-gnu/7/include/stdbool.h'

could be that cxx_builtin_include_directory part of the generated CROSSTOOL files are not generated correctly on these workers?