zlib: Suppress some MSVC warnings

Restore the warning suppression code added by commit 0e4571d25c (ENH:
Initial import from VTK, 2005-01-26, v2.4.0~2414) and commit 3edcd70754
(ENH: Update zlib to 1.2.3, 2007-09-11, v2.6.0~1135).
1 file changed