Fix build on systems without A_ITALIC

Unfortunately, this font style doesn't work in X11 either in that case.

liberty

@@ -1 +1 @@
-Subproject commit 717c30120790e5b1d8b11231996f70f30a1dada8
+Subproject commit 4c2874649d4b1d2414793d60915d309f0bf67117

nncmpp.c

@@ -4194,7 +4194,11 @@ info_tab_format_decode_toggle (char c)
 	case '\x01':
 		return A_BOLD;
 	case '\x02':
+#ifdef A_ITALIC
 		return A_ITALIC;
+#else
+		return A_UNDERLINE;
+#endif
 	default:
 		return 0;
 	}