Output: Report class friends

Report in Class elements a befriending="" attribute listing the class
friends.  Queue the friends for output, but not necessarily as complete
types.

1 files changed, 6 insertions, 0 deletions

diff --git a/test/input/Class-friends.cxx b/test/input/Class-friends.cxx
new file mode 100644
index 0000000..6659db2
--- /dev/null
+++ b/test/input/Class-friends.cxx
@@ -0,0 +1,6 @@
+class A {};
+void f(void);
+class start {
+  friend class A;
+  friend void f(void);
+};