Sync doc comment with upstream

diff --git a/lib/libz/zlib.h b/lib/libz/zlib.h
index 929eb0f..13d8357 100644 (file)
--- a/lib/libz/zlib.h
+++ b/lib/libz/zlib.h
@@ -320,8 +320,8 @@ ZEXTERN int ZEXPORT deflate(z_streamp strm, int flush);
   with the same value of the flush parameter and more output space (updated
   avail_out), until the flush is complete (deflate returns with non-zero
   avail_out).  In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
-  avail_out is greater than six to avoid repeated flush markers due to
-  avail_out == 0 on return.
+  avail_out is greater than six when the flush marker begins, in order to avoid
+  repeated flush markers upon calling deflate() again when avail_out == 0.
 
     If the parameter flush is set to Z_FINISH, pending input is processed,
   pending output is flushed and deflate returns with Z_STREAM_END if there was