On Windows 11, when playing windowed in a separate window/widget from the main emulator window, we don't want the window to have rounded corners, as it prevents the corner pixels from being visible
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
This function does *not* always convert from UTF-16. It converts
from UTF-16 on Windows and UTF-32 on other operating systems.
Also renaming UTF8ToUTF16 for consistency, even though it
technically doesn't have the same problem since it only was
implemented on Windows.
