Use host_tools from cipd on Windows

Bug: 118
Change-Id: I43d4cbaa3d3e6f4c4bf67be3a16a8389ae62a984
diff --git a/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json b/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json
index d7df4c8..02a83ad 100644
--- a/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json
+++ b/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json
@@ -89,9 +89,9 @@
         ]
     },
     {
-        "path": "pigweed/host_tools/${os=linux}-${arch=amd64}",
+        "path": "pigweed/host_tools/${os=linux,windows}-${arch=amd64}",
         "tags": [
-            "git_revision:25527c09720fcc8920f21ee5c93f71ee636ea96a"
+            "git_revision:4a257c1bc592f355c4a9bb712c322d1a45cacfb8"
         ],
         "_comment": "TODO(pwbug/118) Put Windows and Mac host tools in CIPD."
     }
diff --git a/pw_env_setup/py/pw_env_setup/host_build_setup.py b/pw_env_setup/py/pw_env_setup/host_build_setup.py
index 1404c83..05a552a 100644
--- a/pw_env_setup/py/pw_env_setup/host_build_setup.py
+++ b/pw_env_setup/py/pw_env_setup/host_build_setup.py
@@ -42,7 +42,7 @@
     host_dir = os.path.join(pw_root, 'out', 'host')
     env.prepend('PATH', os.path.join(host_dir, 'host_tools'))
 
-    if platform.system() == 'Linux':
+    if platform.system() in ('Linux', 'Windows'):
         env.echo('  skipping host tools setup--got from CIPD')
         return