Reimplement the WMAddListItem macro in Rust.

This was originally a macro in C. We reimplement it as a Rust function.

WINGs/wings-rs/Makefile.am

@@ -6,6 +6,7 @@ RUST_SOURCES = \
 	src/configuration.rs \
 	src/font.rs \
 	src/lib.rs \
+	src/list.rs \
 	src/pango_extras.rs \
 	src/screen.rs
 

WINGs/wings-rs/src/lib.rs

@@ -6,5 +6,6 @@ pub mod WINGsP;
 pub mod button;
 pub mod configuration;
 pub mod font;
+pub mod list;
 pub(crate) mod pango_extras;
 pub mod screen;

WINGs/wings-rs/src/list.rs

@@ -0,0 +1,14 @@
+pub mod ffi {
+    use crate::WINGsP::*;
+
+    use std::ffi::c_char;
+
+    /// Appends an item with the label `text` to `list`.
+    ///
+    /// ## Rust rewrite notes
+    ///
+    /// This was originally a macro.
+    pub unsafe fn WMAddListItem(list: *mut WMList, text: *const c_char) -> *mut WMListItem {
+        unsafe { WMInsertListItem(list, -1, text) }
+    }
+}