Added is_system header file property to JSON include diagram generator

src/common/model/source_file.h

@@ -117,6 +117,20 @@ public:
      */
     source_file_t type() const { return type_; }
 
+    /**
+     * Set whether the file is a system header
+     *
+     * @param is_system Whether the file is a system header
+     */
+    void set_system_header(bool is_system) { is_system_header_ = is_system; }
+
+    /**
+     * Is the file a system header?
+     *
+     * @return True, if the source file is a system header
+     */
+    bool is_system_header() const { return is_system_header_; }
+
     /**
      * Get the source file's parent path.
      *
@@ -185,6 +199,7 @@ private:
     filesystem_path path_{path_type::kFilesystem};
     source_file_t type_{source_file_t::kDirectory};
     bool is_absolute_{false};
+    bool is_system_header_{false};
 };
 } // namespace clanguml::common::model