title: please tell me a better way to have a multiplatform WORKSPACE in Bazel
body: <p>This is an example in my actual WORKSPACE to enable TUT (Template Unit Test) to be seen by my projects, whether I am testing them on Windows or Linux.</p>
  
  <pre><code>new_local_repository(
      name = "win32_tut",
      path = "/d/diego/progs/c++/lib/tut/",
      build_file_content = """
  cc_library(
      name = "tut",
      srcs = glob([
          "tut/*.hpp",
      ]),
      hdrs = glob([
          "*.h",
      ]),
      visibility = ["//visibility:public"],
  )
  """,
  )
  
  new_local_repository(
      name = "linux_tut",
      path = "/usr/include/",
      build_file_content = """
  cc_library(
      name = "tut",
      srcs = glob([
          "tut/*.hpp",
      ]),
      hdrs = glob([
          "tut.h",
      ]),
      visibility = ["//visibility:public"],
  )
  """,
  )
  
  new_local_repository(
      name = "tut",
      path = ".",
      build_file_content = """
  cc_library(
      name = "tut",
      deps = select({
          "@bazel_tools//src/conditions:windows": ["@win32_tut//:tut"],
          "//conditions:default": ["@linux_tut//:tut"],
      }),
      visibility = ["//visibility:public"],
  )
  """,
  )
  </code></pre>
  
  <p>All my cc_test rules are successfully depending on <code>"@tut//:tut"</code>.
  That is working for me, but it looks like I am abusing the WORKSPACE file. Is there a better way to achieve this?</p>