GLK: JACL: Fix Missing Default Switch Cases

These are flagged by GCC if -Wswitch-default is enabled.

engines/glk/jacl/interpreter.cpp

@@ -3426,6 +3426,8 @@ int select_next() {
 				}
 			}
 			break;
+		default:
+			break;
 		}
 	}
 

engines/glk/jacl/libcsv.cpp

@@ -176,6 +176,8 @@ int csv_fini(struct csv_parser *p, void (*cb1)(void *, size_t, void *), void (*c
 		SUBMIT_ROW(p, -1);
 	case ROW_NOT_BEGUN: /* Already ended properly */
 		;
+	default:
+		break;
 	}
 
 	/* Reset parser */

engines/glk/jacl/utils.cpp

@@ -95,6 +95,8 @@ char *strip_return(char *string) {
 		case '\n':
 			string[index] = 0;
 			break;
+		default:
+			break;
 		}
 	}