[bazel] Add Bazel build support

Content of BUILD.bazel is adapted from google3

Bug: 112636

Change-Id: I4bf14a668d09856d1d8bd2f465441464cfe50853
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/zlib/+/770802
Reviewed-by: David Turner <digit@google.com>
2 files changed