build: Add meson build

Change-Id: Id01834cf0b6580b7e6f6fa195b4a547fd03222ce
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/gen/meson.build b/gen/meson.build
new file mode 100644
index 0000000..af850f2
--- /dev/null
+++ b/gen/meson.build
@@ -0,0 +1,14 @@
+# Generated file; do not modify.
+sdbuspp_gen_meson_ver = run_command(
+    sdbuspp_gen_meson_prog,
+    '--version',
+).stdout().strip().split('\n')[0]
+
+if sdbuspp_gen_meson_ver != 'sdbus++-gen-meson version 2'
+    warning('Generated meson files from wrong version of sdbus++-gen-meson.')
+    warning(
+        'Expected "sdbus++-gen-meson version 2", got:',
+        sdbuspp_gen_meson_ver
+    )
+endif
+