Windows 7: Binary packages are not fully functional for non-administrators

When a binary package is installed on Windows 7, any file patched or created by the installer (as opposed to being installed by the installer) has different permissions to the installed files, and cannot be read by an unprivileged user.

This includes qconfig.h, qmake.cache and bin*.prl.

While the tools and demos still work, the user cannot compile any code against the binaries in the package.