sdbus++: add common header file

There are some items generated under server and client which are
overlapping and some currently in server that will also be needed
for async bindings.  Create a common header file that they can
all include in order to reduce the content generated across all these
types.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Id7af8542613503dbd745158c89892ca252eadf5a
diff --git a/tools/meson.build b/tools/meson.build
index f260f61..f7406c9 100644
--- a/tools/meson.build
+++ b/tools/meson.build
@@ -1,8 +1,8 @@
 sdbusplusplus_depfiles = files(
   'sdbus++',
+  'sdbusplus/__init__.py',
   'sdbusplus/enum.py',
   'sdbusplus/error.py',
-  'sdbusplus/__init__.py',
   'sdbusplus/interface.py',
   'sdbusplus/main.py',
   'sdbusplus/method.py',
@@ -14,6 +14,7 @@
   'sdbusplus/templates/error.hpp.mako',
   'sdbusplus/templates/error.md.mako',
   'sdbusplus/templates/interface.client.hpp.mako',
+  'sdbusplus/templates/interface.common.hpp.mako',
   'sdbusplus/templates/interface.md.mako',
   'sdbusplus/templates/interface.server.cpp.mako',
   'sdbusplus/templates/interface.server.hpp.mako',