Fixed up before doing the upgrade to SFML 3.0

meson.build

@@ -3,12 +3,17 @@ project('sfmldemo', 'cpp',
 
 dependencies = [
   dependency('sfml'),
-  dependency('imgui-sfml'),
-  dependency('fmt'),
+  subproject('fmt').get_variable('fmt_dep'),
   dependency('box2d'),
 ]
 
-executable('sfmldemo', 'main.cpp',
+source = [
+  'dbc.cpp',
+  'main.cpp'
+]
+
+executable('sfmldemo',
+  source,
   win_subsystem: 'windows',
   cpp_args: '-DFMT_HEADER_ONLY',
   dependencies: dependencies)