vkd3d-compiler: Define debug channel

We need this if we include vkd3d_shader since the memory include header got fixed.

Signed-off-by: Joshua Ashton <joshua@froggi.es>

programs/vkd3d-compiler/main.c

@@ -16,6 +16,8 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  */
 
+#define VKD3D_DBG_CHANNEL VKD3D_DBG_CHANNEL_API
+
 #include <fcntl.h>
 #include <stdbool.h>
 #include <stdio.h>