New debug scheme with explicit debug channels declaration.

diff --git a/windows/caret.c b/windows/caret.c
index b0f04d3..d66a03b 100644
--- a/windows/caret.c
+++ b/windows/caret.c
@@ -10,6 +10,8 @@
 #include "module.h"
 #include "debug.h"
 
+DEFAULT_DEBUG_CHANNEL(caret)
+
 typedef struct
 {
     HWND     hwnd;