Make zlib headers compatible with MSVC

- MSVC does not provide unistd.h, so we exclude it when we are
  using clang with msvc.

Change-Id: I9a57e61a900d46169f4f76c9bbc1295650b41e2a

1 files changed, 3 insertions, 1 deletions

diff --git a/zconf.h b/zconf.h
index 5e1d68a..92612bf 100644
--- a/zconf.h
+++ b/zconf.h
@@ -472,7 +472,9 @@ typedef uLong FAR uLongf;
 #endif
 #ifndef Z_SOLO
 #  if defined(Z_HAVE_UNISTD_H) || defined(_LARGEFILE64_SOURCE)
-#    include <unistd.h>         /* for SEEK_*, off_t, and _LFS64_LARGEFILE */
+#    ifndef _MSC_VER
+#      include <unistd.h>         /* for SEEK_*, off_t, and _LFS64_LARGEFILE */
+#    endif
 #    ifdef VMS
 #      include <unixio.h>       /* for off_t */
 #    endif