[buildcore] Windows fixes

deps/buildcore/scripts/pybb.py

@@ -14,6 +14,7 @@
 import os
 import platform
 import shutil
+import socket
 import subprocess
 import sys
 from typing import List, Optional
@@ -115,7 +116,7 @@ def hostname() -> int:
 
 
 def host_env() -> int:
-    os_name = os.uname().sysname.lower()
+    os_name = socket.gethostname().lower()
     arch = platform.machine()
     if arch == 'amd64':
         arch = 'x86_64'