zlib is not exposed to libziparchive headers

By forward-declaring zstream, we don't need to re-export zlib headers.

Bug: 37342627
Test: build
Test: BOARD_VNDK_VERSION=current m -j dumpstate (or any other module
using libziparchive)

Change-Id: Ia69e5d459c79878d491cfe4ca21a7cc8fed4a5d8

libziparchive/include/ziparchive/zip_writer.h

@@ -17,7 +17,6 @@
 #ifndef LIBZIPARCHIVE_ZIPWRITER_H_
 #define LIBZIPARCHIVE_ZIPWRITER_H_
 
-#include <zlib.h>
 #include <cstdio>
 #include <ctime>
 
@@ -28,6 +27,9 @@
 #include "android-base/macros.h"
 #include "utils/Compat.h"
 
+struct z_stream_s;
+typedef struct z_stream_s z_stream;
+
 /**
  * Writes a Zip file via a stateful interface.
  *