fop(1), hru(1), intcmp(1), mm(1), rpn(1), swab(1): fixes conditional compilation

src/fop.rs

@@ -39,7 +39,7 @@ fn main() {
 	let mut d = '\u{1E}'.to_string(); /* ASCII record separator */
 	let mut optind = 1;
 
-	if cfg!(target_os="openbsd") {
+	#[cfg(target_os="openbsd")] {
 		let promises = Promises::new("stdio proc exec");
 		if let Err(e) = pledge(Some(promises), None) {
 			eprintln!("{}: {}", argv[0], e.strerror());