message: Fix envoy-filter-example build
  Some of the references to "//bazel:windows_x86_64" were not properly prefixed with the repostory name, causing the build of envoy-filter-example to fail.
  Risk Level: Low
  Testing:
  bazel test //test/...
  From envoy-filter-example, ran bazel build //:envoy
  Docs Changes:
  Release Notes:
diff: @@ -28,7 +28,7 @@ def envoy_copts(repository, test = False):
  ]
  return select({
  - "//bazel:windows_x86_64": msvc_options,
  + repository + "//bazel:windows_x86_64": msvc_options,
  "//conditions:default": posix_options,
  }) + select({
  # Bazel adds an implicit -DNDEBUG for opt.
  @@ -67,7 +67,7 @@ def envoy_linkopts():
  "-pagezero_size 10000",
  "-image_base 100000000",
  ],
  - "//bazel:windows_x86_64": [
  + "@envoy//bazel:windows_x86_64": [
  "-DEFAULTLIB:advapi32.lib",
  ],
  "//conditions:default": [
  @@ -85,7 +85,7 @@ def _envoy_stamped_linkopts():
  #
  # /usr/bin/ld.gold: internal error in write_build_id, at ../../gold/layout.cc:5419
  "@envoy//bazel:coverage_build": [],
  - "//bazel:windows_x86_64": [],
  + "@envoy//bazel:windows_x86_64": [],
  # MacOS doesn't have an official equivalent to the `.note.gnu.build-id`
  # ELF section, so just stuff the raw ID into a new text section.
  @@ -519,6 +519,6 @@ def envoy_select_force_libcpp(if_libcpp, default = None):
  return select({
  "@envoy//bazel:force_libcpp": if_libcpp,
  "@bazel_tools//tools/osx:darwin": [],
  - "//bazel:windows_x86_64": [],
  + "@envoy//bazel:windows_x86_64": [],
  "//conditions:default": default or [],
  })
  