Merge pull request #2512 from umarcor/plugin-err

plugin: enhance no-plugin error

passes/cmds/plugin.cc

@@ -93,7 +93,11 @@ void load_plugin(std::string filename, std::vector<std::string> aliases)
 #else
 void load_plugin(std::string, std::vector<std::string>)
 {
-	log_error("This version of yosys is built without plugin support.\n");
+	log_error(
+		"\n  This version of Yosys cannot load plugins at runtime.\n"
+		"  Some plugins may have been included at build time.\n"
+		"  Use option `-H' to see the available built-in and plugin commands.\n"
+	);
 }
 #endif