add a comment about xmalloc; it needs to go away
diff --git a/lib/diffreg.c b/lib/diffreg.c
index 2e83f53..544c14d 100644
--- a/lib/diffreg.c
+++ b/lib/diffreg.c
@@ -88,7 +88,7 @@
#include "got_diff.h"
#include "diff.h"
-#include "xmalloc.h"
+#include "xmalloc.h" /* XXX should return GOT_ERR_NO_MEM instead of exiting */
#define MINIMUM(a, b) (((a) < (b)) ? (a) : (b))
#define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b))