slight modification of the semantics of std.os.getenvW
slight modification of the semantics of std.os.getenvW

Now, this function first attempts a case-sensitive lookup.
If no match is found, and `key` is ASCII, then it attempts a
second case-insensitive lookup.

It is not planned to support full Unicode case-insensitivity
on Windows, and in fact relying on non-ASCII case-insensitive
environment variables is fundamentally problematic.

raulgrell/zig,raulgrell/zig,zig-lang/zig,raulgrell/zig,zig-lang/zig,raulgrell/zig,raulgrell/zig,andrewrk/zig,andrewrk/zig,zig-lang/zig