Patch zlib to fix compatibility with latest Xcode

Fixes bazelbuild#17956

Partial commit for third_party/*, see bazelbuild#17987.

Closes bazelbuild#17987

Signed-off-by: Yun Peng <[email protected]>

Author: meteorcloudy

third_party/zlib/gzguts.h

@@ -3,6 +3,10 @@
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
+#ifndef _WIN32
+  #include <unistd.h>
+#endif
+
 #ifdef _LARGEFILE64_SOURCE
 #  ifndef _LARGEFILE_SOURCE
 #    define _LARGEFILE_SOURCE 1

third_party/zlib/zlib.patch

@@ -0,0 +1,15 @@
+diff --git a/third_party/zlib/gzguts.h b/third_party/zlib/gzguts.h
+index 57faf37165..54f668fcb2 100644
+--- a/third_party/zlib/gzguts.h
++++ b/third_party/zlib/gzguts.h
+@@ -3,6 +3,10 @@
+  * For conditions of distribution and use, see copyright notice in zlib.h
+  */
+ 
++#ifndef _WIN32
++  #include <unistd.h>
++#endif
++
+ #ifdef _LARGEFILE64_SOURCE
+ #  ifndef _LARGEFILE_SOURCE
+ #    define _LARGEFILE_SOURCE 1