fix: Fix nightly and #define support.

Author: Hywan

build.rs

@@ -1,4 +1,6 @@
 fn main() {
+    println!("cargo:rustc-check-cfg=cfg(nightly)");
+
     if rustc_version::version_meta().unwrap().channel == rustc_version::Channel::Nightly {
         println!("cargo:rustc-cfg=nightly");
     }

macros/README.md

@@ -1,4 +1,4 @@
 # `inline-c-macro`
 
-please check the [`readme.md` of the `inline-c`
+Please check the [`readme.md` of the `inline-c`
 crate](https://github.com/hywan/inline-c-rs) to learn more.

macros/build.rs

@@ -1,4 +1,6 @@
 fn main() {
+    println!("cargo:rustc-check-cfg=cfg(nightly)");
+
     if rustc_version::version_meta().unwrap().channel == rustc_version::Channel::Nightly {
         println!("cargo:rustc-cfg=nightly");
     }

macros/src/lib.rs

@@ -1,5 +1,7 @@
 //! Please see the `inline-c` crate to learn more.
 
+#![cfg_attr(nightly, feature(proc_macro_span))]
+
 use proc_macro2::TokenStream;
 use quote::quote;
 
@@ -114,14 +116,18 @@ fn reconstruct(input: TokenStream) -> String {
 
                                 #[cfg(nightly)]
                                 {
-                                    let current_line = define.span().start().line;
+                                    // `Span::start()` doesn't work on `proc_macro2`, we need to fallback to
+                                    // `proc_macro` itself, see https://github.com/dtolnay/proc-macro2/issues/402.
+                                    let current_line = define.span().unwrap().start().line();
                                     iterator.next();
                                     output.push_str("define ");
 
                                     loop {
                                         match iterator.peek() {
                                             Some(item) => {
-                                                if item.span().start().line == current_line {
+                                                if item.span().unwrap().start().line()
+                                                    == current_line
+                                                {
                                                     output.push_str(&item.to_string());
                                                     iterator.next();
                                                 } else {

src/run.rs

@@ -200,7 +200,6 @@ fn command_add_linker_flags_msvc(command: &mut Command, variables: &HashMap<Stri
 mod tests {
     use super::*;
     use crate::predicates::*;
-    use std::env::{remove_var, set_var};
 
     #[test]
     fn test_run_c() {
@@ -220,8 +219,12 @@ mod tests {
         .success()
         .stdout(predicate::eq("Hello, World!\n").normalize());
     }
+
+    #[cfg(not(target_os = "macos"))] // macOS doesn't support `--defsym`
     #[test]
     fn test_run_c_ldflags() {
+        use std::env::{remove_var, set_var};
+
         let host = target_lexicon::HOST.to_string();
         let msvc = host.contains("msvc");
         if msvc {