wrap: parse env-if-host options as filenames instead of strings
If we parse the "env-if-host" options as "G_OPTION_ARG_STRING_ARRAY", Glib assumes them to be encoded with the current locale. This can be an issue when pressure-vessel needs to run the main game, because Steam will set "LC_ALL=C", but the "env-if-host" might still contain characters that are not ASCII. To solve this we use "G_OPTION_ARG_FILENAME_ARRAY" that treats the options as opaque byte-blobs.
Fixes: #52 (closed) Fixes: steam-runtime#349