Fix Unicode $USER (#2278)

* Fix Unicode $USER

When `$USER` contains Unicode then cmd.exe will return `%AppData%` in Windows Code Page which won't be recognized by Linux/grep.

So make sure it outputs result in UTF-8 instead.

src/winetricks

@@ -1054,7 +1054,7 @@ w_pathconv()
 # Expand an environment variable and print it to stdout
 w_expand_env()
 {
-    winetricks_early_wine_arch cmd.exe /c echo "%$1%"
+    winetricks_early_wine_arch cmd.exe /c "chcp 65001 > nul && echo %$1%"
 }
 
 # Determine what architecture a binary file is built for, silently continue in case of failure.