w32api:

w32api:

        * include/winioctl.h (FSCTL_SET_SPARSE): Define.

cygwin:

        * wincap.h (wincaps::supports_sparse_files): New flag.
        (wincapc::supports_sparse_files): New method.
        * wincap.cc (wincap_unknown): Define value for the new flag.
        (wincap_95): Ditto.
        (wincap_95osr2): Ditto.
        (wincap_98): Ditto.
        (wincap_98se): Ditto.
        (wincap_me): Ditto.
        (wincap_nt3): Ditto.
        (wincap_nt4): Ditto.
        (wincap_nt4sp4): Ditto.
        (wincap_2000): Ditto.
        (wincap_xp): Ditto.
        * path.h (path_conv::fs_flags): New method.
        * fhandler_disk_file.cc: Include winioctl.h for DeviceIoControl.
        (fhandler_disk_file::open): Set newly created and truncated files as
        sparse on platforms that support it.