Latest code, hopefully stable.

meson.build

@@ -28,6 +28,11 @@ if not json_result.found()
   error('json module is required')
 endif
 
+pluggy_result = python.find_installation('python3', modules:['pluggy'], required: false)
+if not pluggy_result.found()
+  error('pluggy module is required')
+endif
+
 # End users might not have the Gtk development libraries installed, making pkg-config fail.
 # Therefore, check this dependency via python.
 gtk_major_version = '3'
@@ -50,7 +55,6 @@ optional_modules = {
   'brlapi': 'braille output',
   'louis': 'contracted braille',
   'speechd': 'speech output',
-  'pluggy': 'plugin system',
   'dasbus': 'D-Bus remote controller',
   'psutil': 'system information commands',
   'gi.repository.Wnck': 'mouse review',