sdbus++: async: server: generate signal emit fns

Populate enough of the generator to define the basic class structure
and generate bindings for emitting signals.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: If62c323f460fc8c73a3aca495e5b89cd84bab32a
diff --git a/example/meson.build b/example/meson.build
index 75b265c..c7ebf61 100644
--- a/example/meson.build
+++ b/example/meson.build
@@ -65,6 +65,15 @@
 )
 
 executable(
+    'calculator-aserver',
+    'calculator-aserver.cpp',
+    generated_sources,
+    implicit_include_directories: false,
+    include_directories: include_directories('gen'),
+    dependencies: sdbusplus_dep,
+)
+
+executable(
     'calculator-client',
     'calculator-client.cpp',
     generated_sources,