diff --git a/code/qcommon/unzip.c b/code/qcommon/unzip.c
index ac956091..7daf271b 100644
--- a/code/qcommon/unzip.c
+++ b/code/qcommon/unzip.c
@@ -4048,7 +4048,7 @@ int inflateInit2_(z_streamp z, int w, const char *version, int stream_size)
 
   /* create inflate_blocks state */
   if ((z->state->blocks =
-      inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
+      inflate_blocks_new(z, z->state->nowrap ? ((check_func)0) : adler32, (uInt)1 << w))
       == Z_NULL)
   {
     inflateEnd(z);