For Windows, the Subsurface installers do not include
the file "qwindowsvistastyle.dll" required to make the
applications that are published to have a native look.
Modify the MXE *build.sh scripts to include the
file as "plugins/styles/qwindowsvistastyle.dll".
Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>