#12098: Make multiprocessing's child processes inherit sys.flags on Windows

Initial patch by Sergey Mezentsev.
diff --git a/Lib/multiprocessing/forking.py b/Lib/multiprocessing/forking.py
index 2729afe..eadc321 100644
--- a/Lib/multiprocessing/forking.py
+++ b/Lib/multiprocessing/forking.py
@@ -324,7 +324,8 @@
             return [sys.executable, '--multiprocessing-fork']
         else:
             prog = 'from multiprocessing.forking import main; main()'
-            return [_python_exe, '-c', prog, '--multiprocessing-fork']
+            opts = util._args_from_interpreter_flags()
+            return [_python_exe] + opts + ['-c', prog, '--multiprocessing-fork']
 
 
     def main():