diff --git a/deps/zlib/ioapi.h b/deps/zlib/ioapi.h
index 14bf58c648..a6332ed3d9 100644
--- a/deps/zlib/ioapi.h
+++ b/deps/zlib/ioapi.h
@@ -54,7 +54,7 @@
  #if (_MSC_VER >= 1400) && (!(defined(NO_MSCVER_FILE64_FUNC)))
   #define ftello64 _ftelli64
   #define fseeko64 _fseeki64
- #else // old MSC
+ #else /* old MSC */
   #define ftello64 ftell
   #define fseeko64 fseek
  #endif
@@ -178,8 +178,8 @@ typedef struct zlib_filefunc64_32_def_s
 
 #define ZREAD64(filefunc,filestream,buf,size)     ((*((filefunc).zfile_func64.zread_file))   ((filefunc).zfile_func64.opaque,filestream,buf,size))
 #define ZWRITE64(filefunc,filestream,buf,size)    ((*((filefunc).zfile_func64.zwrite_file))  ((filefunc).zfile_func64.opaque,filestream,buf,size))
-//#define ZTELL64(filefunc,filestream)            ((*((filefunc).ztell64_file)) ((filefunc).opaque,filestream))
-//#define ZSEEK64(filefunc,filestream,pos,mode)   ((*((filefunc).zseek64_file)) ((filefunc).opaque,filestream,pos,mode))
+/* #define ZTELL64(filefunc,filestream)            ((*((filefunc).ztell64_file)) ((filefunc).opaque,filestream)) */
+/* #define ZSEEK64(filefunc,filestream,pos,mode)   ((*((filefunc).zseek64_file)) ((filefunc).opaque,filestream,pos,mode)) */
 #define ZCLOSE64(filefunc,filestream)             ((*((filefunc).zfile_func64.zclose_file))  ((filefunc).zfile_func64.opaque,filestream))
 #define ZERROR64(filefunc,filestream)             ((*((filefunc).zfile_func64.zerror_file))  ((filefunc).zfile_func64.opaque,filestream))