Require {DECLARE,DEFAULT}_DEBUG_CHANNEL statements to end in a ;

diff --git a/graphics/env.c b/graphics/env.c
index e4af5a6..e21c385 100644
--- a/graphics/env.c
+++ b/graphics/env.c
@@ -13,7 +13,7 @@
 #include "debugtools.h"
 #include "heap.h"
 
-DEFAULT_DEBUG_CHANNEL(gdi)
+DEFAULT_DEBUG_CHANNEL(gdi);
 
 typedef struct {
         ATOM atom;