Update README and fix build docs mistake.

README.md

@@ -46,6 +46,8 @@ What works?
 Changelog
 --------------------
 #### [Unreleased]
+- Fix cfg warnings <https://github.com/sequenceplanner/r2r/commit/4cb5bd362e81154924cc7dc21f8edbf470c4604a>
+- More convinent one time parameter access <https://github.com/sequenceplanner/r2r/pull/107>
 
 #### [0.9.1] - 2024-10-12
 - Minor code fixes: <https://github.com/sequenceplanner/r2r/pull/105>, <https://github.com/sequenceplanner/r2r/pull/106>

r2r_common/src/lib.rs

@@ -150,6 +150,10 @@ pub fn print_cargo_ros_distro() {
     }
 }
 
+#[cfg(feature = "doc-only")]
+pub fn print_cargo_used_cfgs(_message_cfgs: &[&str]) {}
+
+#[cfg(not(feature = "doc-only"))]
 pub fn print_cargo_used_cfgs(message_cfgs: &[&str]) {
     // Declare all supported ros distros as cfg directives for cargo
     for d in SUPPORTED_ROS_DISTROS {

r2r_rcl/src/lib.rs

@@ -1,12 +1,12 @@
 #![allow(non_upper_case_globals)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
-#![allow(improper_ctypes)]
 #![allow(dead_code)]
 // Silence "`extern` fn uses type `u128`, which is not FFI-safe"
 // As of rustc 1.78, this has been fixed.
 // It could be good to still warn if building with an older rust version.
 #![allow(improper_ctypes)]
+#![allow(improper_ctypes_definitions)]
 include!(concat!(env!("OUT_DIR"), "/rcl_bindings.rs"));
 
 use std::ffi::{CStr, CString};