Automatically tag systemtap files

docs/markdown/Installing.md

@@ -184,6 +184,8 @@ time, please help extending the list of well known categories.
     developers (i.e. build tools).
 - `tests`:
   * Files installed into `installed-tests` subdir (*Since 0.64.0*).
+- `systemtap`:
+  * Files installed into `systemtap` subdir (*Since 0.64.0*).
 
 Custom installation tag can be set using the `install_tag` keyword argument
 on various functions such as [[custom_target]], [[configure_file]],

mesonbuild/backend/backends.py

@@ -1542,6 +1542,8 @@ class Backend:
             return 'i18n'
         elif 'installed-tests' in dest_path.parts:
             return 'tests'
+        elif 'systemtap' in dest_path.parts:
+            return 'systemtap'
         mlog.debug('Failed to guess install tag for', dest_path)
         return None