sdbus++: async: server: add generator stub

Add the needful changes in the tools and meson-generator to
create an asynchronous server binding header.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I0607aefc006eafb9224d92b887cf2d3b30c8da06
diff --git a/tools/sdbus++-gen-meson b/tools/sdbus++-gen-meson
index 9dcae96..2de2032 100755
--- a/tools/sdbus++-gen-meson
+++ b/tools/sdbus++-gen-meson
@@ -36,7 +36,7 @@
 ## if a repository contains old copies of the generated meson.build files and
 ## needs an update.  We should increment the version number whenever the
 ## resulting meson.build would change.
-tool_version="sdbus++-gen-meson version 6"
+tool_version="sdbus++-gen-meson version 7"
 function show_version() {
     echo "${tool_version}"
 }
@@ -190,6 +190,7 @@
             interface.yaml)
                 outputs="${outputs}'common.hpp', "
                 outputs="${outputs}'server.cpp', 'server.hpp', "
+                outputs="${outputs}'aserver.hpp', "
                 outputs="${outputs}'client.hpp', "
                 ;;
 
@@ -307,6 +308,7 @@
         ${sdbusppcmd} interface server-header "${intf}" > "${outputdir}/server.hpp"
         ${sdbusppcmd} interface server-cpp "${intf}" > "${outputdir}/server.cpp"
         ${sdbusppcmd} interface client-header "${intf}" > "${outputdir}/client.hpp"
+        ${sdbusppcmd} interface aserver-header "${intf}" > "${outputdir}/aserver.hpp"
     fi
 
     if [[ -e "${rootdir}/$1.errors.yaml" ]]; then