--- a/python/mozbuild/mozbuild/base.py
+++ b/python/mozbuild/mozbuild/base.py
@@ -454,17 +454,17 @@ class MozbuildObject(ProcessExecutionMix
         append_env[b'MACH'] = '1'
 
         params = {
             'args': args,
             'line_handler': line_handler,
             'append_env': append_env,
             'explicit_env': explicit_env,
             'log_level': logging.INFO,
-            'require_unix_environment': True,
+            'require_unix_environment': False,
             'ensure_exit_code': ensure_exit_code,
             'pass_thru': pass_thru,
 
             # Make manages its children, so mozprocess doesn't need to bother.
             # Having mozprocess manage children can also have side-effects when
             # building on Windows. See bug 796840.
             'ignore_children': True,
         }