Windows RC files can have strings expressed either as narrow
chars expressed in a specific codepage, or as wide unicode strings.
Regardless of which way they are expressed, they are converted into
unicode strings in the compiled resource files.

When using narrow strings, even if using escaped chars like \251,
those chars are interpreted according to a specific codepage. The
codepage can be specified with arguments to the RC/windres tool
(or with a pragma, but not all tools support the pragmas),
but when no codepage is specified, the exact interpretation varies.

llvm-rc uses a hard stance of defaulting to only accepting ANSI
chars unless something else has been specified (and pragmas aren't
supported). llvm-windres defaults to CP 850 though, for compatibility
with what most people probably intend to.

However, GNU windres and MS rc.exe actually default to what the
system's current default codepage is. That means that if the resource
file is built on a machi...