c677bac875 changed the order here, but
this also resulted in the string having whatever size was necessary for
the install data path, rather than being large enough to fit a userdata
path. To fix this, move the resize operaetion *after* the buit-in
themes are searched, and also bump it to 1024 just to be sure.
This resulted in a crash due to a bug in os_get_path_internal() which
will need to be fixed separately.
As of 8dcfae9a39, indicating the base
style to the proxy is completely functional.
It also bypasses QT_STYLE_OVERRIDE and -style, but since the system
theme is no longer available on Linux this is a non-issue.
