https://bugs.gentoo.org/895298

--- a/src/decls.hpp
+++ b/src/decls.hpp
@@ -23,6 +23,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "config.h"

 #include "umlPackage.hpp"
+#include <cinttypes>

 /* Package processing auxiliary structure:
    "Declarations" are UML packages (which map to IDL module or C++