gzio: fix multiple definition of gzio_stream_s.

Failed on Cygwin.

* gzio.c (gzio_stream_s): Variable defined here.

* gzio.h (gzio_stream_s): Turn to declaration with extern.

1 files changed, 2 insertions, 0 deletions

diff --git a/gzio.c b/gzio.c
index 2485201a..bbdc1d45 100644
--- a/gzio.c
+++ b/gzio.c
@@ -61,6 +61,8 @@ struct gzio_handle {
   unsigned is_output : 8;
 };
 
+val gzio_stream_s;
+
 struct cobj_class *gzio_stream_cls;
 
 static void gzio_stream_print(val stream, val out, val pretty,