Remove dependency on nightly Rust

examples/msp430-help/main.rs

@@ -1,7 +1,6 @@
 // This example contains information adapted from the MSPGCC project's documentation.
 // As such, it is licensed under the GPL, to the extent that such a thing is possible.
 // https://mspgcc.sourceforge.net/manual/ln16.html
-#![feature(decl_macro)]
 
 fn main() {
     println!("Hello, world!")

msp430-asm/src/main.rs

@@ -1,7 +1,6 @@
 // © 2023-2024 John Breaux
 //See LICENSE.md for license
 //! Simple frontend for the assembler
-#![feature(decl_macro)]
 use argp::parse_args_or_exit;
 use libmsp430::{
     assembler::Assemble,
@@ -66,14 +65,16 @@ mod repl {
     use std::io::{stderr, Write};
 
     /// Formats the line number
-    macro linenr($n: expr) {
-        format_args!("{:4}: ", $n)
+    macro_rules! linenr {
+        ($n: expr) => {
+            format_args!("{:4}: ", $n)
+        };
     }
 
     /// [println], but without the newline
-    macro printfl ($($x: expr),+) {
+    macro_rules! printfl {($($x: expr),+) => {
         {print!($($x),+); let _ = ::std::io::stdout().flush();}
-    }
+    }}
 
     /// Runs the read-evaluate-print loop
     pub fn repl(buf: &mut String) -> Result<(), Box<dyn Error>> {