contrib/wix/hg.cmd

util: call warnings.warn() with a sysstr in nouideprecwarn

This preserves nouideprecwarn wanting a bytes, which is consistent
with the rest of hg.

Differential Revision: https://phab.mercurial-scm.org/D2210

@echo off
rem launch hg.exe from parent folder
"%~dp0\..\hg.exe" %*