[Bug 17619] New: GetDriveTypeW says C: is a network share if /home is an NFS share, breaking Steam installer

http://bugs.winehq.org/show_bug.cgi?id=17619

Summary: GetDriveTypeW says C: is a network share if /home is an
                    NFS share, breaking Steam installer
           Product: Wine
           Version: 1.1.16
          Platform: Other
        OS/Version: other
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: kernel32
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Created an attachment (id=19804)
 --> (http://bugs.winehq.org/attachment.cgi?id=19804)
Patch to make C: always report as DRIVE_FIXED type

My /home is an NFS share, this means NtQueryVolumeInformationFile returns the
type of ~/.wine/drive_c as a network share, confusing installers (such as
Steam).

I tracked this down to a problem with GetDriveTypeW querying the volume
information and not even calling get_mountmgr_drive_type in some cases (such as
a network share), so any configuration in winecfg had no effect.

I have attached a patch that causes C: to always report as DRIVE_FIXED, which
fixes my problem, and should avoid any problems of this sort in the future.

However this still means that winecfg overrides have no effect on network
shares, this only fixes the most common problem of C: being considered a
network share.