message: c compatibility for c header
diff: #include <stdint.h>
  #include <wchar.h>
  +#ifdef __cplusplus
  extern "C" {
  +#endif
  /**
  * @defgroup types Builtin Types
  @@ -52,19 +54,21 @@ struct fixed_string16 {
  char str[16];
  };
  -typedef fixed_string16 field_name;
  +typedef struct fixed_string16 field_name;
  struct fixed_string32 {
  uint8_t len;
  char str[32];
  };
  -typedef fixed_string32 type_name;
  +typedef struct fixed_string32 type_name;
  struct account_permission {
  account_name account;
  permission_name permission;
  };
  +#ifdef __cplusplus
  } /// extern "C"
  +#endif
  /// @}
  