unzip fails extraction to vfat

[Timo Teras]

Hi,

It seems that unzip is extra obsessive about mkdir permission errors as
it prevents extraction to vfat where it is not be possible to set all
bits.

Seems that archival/unzip.c:unzip_main() calls bb_make_directory() with
dir_mode to create the final directory component. bb_make_directory()
considers it fatal if chmod() fails. The real unzip command however,
treats this only as a warning situation.

Could we handle this situation the same in busybox? This would make it
simpler to extract files to vfat and other filesystems with limited
permissions support.

Thanks,
 Timo