I have to make filename work correctly under none UTF-8 exec charset. Do not tell me to use locale since locale is not thread-safe and configure locale is a huge issue.
I do not use any C stdio or C++ iostream facilities since I create my own I/O library from scratch. However, this is something I would like to deal with it correctly since none of these libc library does the right thing, they all assume exec-charset is UTF-8 and that just creates format string vulnerabilities silently. If you guys could not correctly support this feature, please just remove that toggle, just like removing trigraph. Clang does not support none UTF-8 exec-charset and no one complains about it. Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10
