Don't create module configuration for dependencies.

SConscript

@@ -100,22 +100,26 @@ def _cook(env: Environment, recipe_name: str):
     _run_cook(dependency)
     return dependency.cook_result
 
-def _normalize_module_path(env: Environment, path: str) -> str:
+def _normalize_module_path(env: Environment, path: str) -> str|None:
     module_root = env.Dir('#/private').abspath
     try:
-        return os.path.relpath(path, module_root)
+        relative = os.path.relpath(path, module_root)
+        if relative[:2] == '..':
+            return None
+        return relative
     except ValueError: # may be thrown on Windows if the module is on a different drive than the project
-        return os.path.normpath(path) # just use the absolute path then
+        return None
 
 def _module(env: Environment, file: str):
     folder = _normalize_module_path(env, env.File(file).dir.abspath)
-    dirname = os.path.basename(folder)
-    env.Append(SPP_MODULES = {folder: _Module(
-        name=dirname,
-        folder=folder,
-        description='',
-        cxx_namespace=dirname
-    )})
+    if folder is not None: # only include modules inside the source tree
+        dirname = os.path.basename(folder)
+        env.Append(SPP_MODULES = {folder: _Module(
+            name=dirname,
+            folder=folder,
+            description='',
+            cxx_namespace=dirname
+        )})
     return SConscript(file, exports = 'env', variant_dir = env['VARIANT_DIR'], src_dir = '.')
 
 def _module_config(env: Environment, **kwargs) -> None:
@@ -302,8 +306,7 @@ def _try_merge_dicts(dictA: dict, dictB: dict) -> 'dict|None':
                 result[key] = mergedValue
             elif valueA != valueB:
                 return None
-            else:
-                result[key] = valueA
+        result[key] = valueA
     for key, valueB in dictB.items():
         if key not in result:
             result[key] = valueB
@@ -459,11 +462,12 @@ def _wrap_builder(builder, target_type: TargetType):
         target.kwargs = kwargs
         target.dependencies = target_dependencies
         module_folder = _normalize_module_path(env, env.Dir('.').abspath)
-        module = env['SPP_MODULES'].get(module_folder)
-        if module is None:
-            env.Warn(f'No module config found for target {target.name} at {module_folder}')
-        else:
-            target.module = module
+        if module_folder is not None:
+            module = env['SPP_MODULES'].get(module_folder)
+            if module is None:
+                env.Warn(f'No module config found for target {target.name} at {module_folder}')
+            else:
+                target.module = module
         env.Append(SPP_TARGETS = [target])
         if not target.dependencies:
             _build_target(target)