title: Can't build a project package using boost/iostream from bazel
body: <p>I am using <a href="https://github.com/nelhage/rules_boost" rel="nofollow noreferrer">https://github.com/nelhage/rules_boost</a> in a bazel project, everything is working fine except when I try to use boost/iostream. 
  The problem occurs on windows 10, and not on linux. boost/iostream depends on zlib and the file that is downloaded is <a href="https://zlib.net/zlib-1.2.11.tar.gz" rel="nofollow noreferrer">https://zlib.net/zlib-1.2.11.tar.gz</a></p>
  
  <p>The error I get is:</p>
  
  <pre><code>ERROR: .../external/net_zlib_zlib/BUILD.bazel:6:1: in cc_library rule @net_zlib_zlib//:zlib: Expected action_config for 'preprocess-assemble' to be configured
  ERROR: Analysis of target '.../storage:storage' failed; build abo
  </code></pre>
  
  <p>rted: Analysis of target '@net_zlib_zlib//:zlib' failed; build aborted</p>
  
  <p>This is the BUILD file:</p>
  
  <pre><code>cc_library(
      name = "storage",
      srcs = [
        "blobstore.cc",
        "blobstore.h",
      ],
      hdrs = [
        "blobstore.h",
      ],
      deps = [
        "@boost//:iostreams",
      ],
      defines = ["BOOST_ALL_NO_LIB"],
  )
  </code></pre>
  
  <p>Does anyone have idea what the problem might be. </p>