introducing a generic logger "class"

common/utils/T/tracer/logger/logger.c

@@ -0,0 +1,11 @@
+#include "logger.h"
+#include "logger_defs.h"
+#include <stdlib.h>
+
+void logger_add_view(logger *_l, view *v)
+{
+  struct logger *l = _l;
+  l->vsize++;
+  l->v = realloc(l->v, l->vsize * sizeof(view *)); if (l->v == NULL) abort();
+  l->v[l->vsize-1] = v;
+}