Many options now have additive effect

For example, -A and -V used to override each other, whereas now:

  -A    report the average amount
  -V    report all amounts at current value
  -AV   report the current value of the average
  -VA   report the average of all current values

1 files changed, 4 insertions, 1 deletions

diff --git a/src/scope.h b/src/scope.h
index 75dc2c0f..31ef61cb 100644
--- a/src/scope.h
+++ b/src/scope.h
@@ -99,10 +99,13 @@ private:
 #endif // HAVE_BOOST_SERIALIZATION
 };
 
+class empty_scope_t;
+
 class scope_t
 {
 public:
-  static scope_t * default_scope;
+  static scope_t *       default_scope;
+  static empty_scope_t * empty_scope;
 
   explicit scope_t() {
     TRACE_CTOR(scope_t, "");