message: add more logging to build script
diff: @@ -63,6 +63,10 @@ struct Library {
  impl Library {
  fn probe_from_paths(pkg_name: &str, link_libs: &str, link_paths: &str, include_paths: &str) -> Result<Self> {
  + eprintln!(
  + "=== Setting up OpenCV library from environment, pkg_name: {}, link_libs: {}, link_paths: {}, include_paths: {}",
  + pkg_name, link_libs, link_paths, include_paths
  + );
  let libs: Vec<_> = link_libs.split(',')
  .map(|x| {
  let mut path = PathBuf::from(x.trim());
  @@ -114,6 +118,7 @@ impl Library {
  #[cfg(not(target_env = "msvc"))]
  fn probe_system(pkg_name: &str) -> Result<Self> {
  + eprintln!("=== Setting up OpenCV library from pkg_config");
  let opencv = pkg_config::probe_library(pkg_name)?;
  Ok(Self {
  pkg_name: pkg_name.to_owned(),
  @@ -129,6 +134,7 @@ impl Library {
  #[cfg(target_env = "msvc")]
  fn probe_system(pkg_name: &str) -> Result<Self> {
  + eprintln!("=== Setting up OpenCV library from vcpkg");
  let opencv = vcpkg::find_package(pkg_name)?;
  let libs = opencv.found_libs.into_iter()
  .filter_map(|lib| lib.file_name()
  @@ -424,7 +430,9 @@ fn probe_opencv() -> Result<Library> {
  } else {
  unreachable!("Feature flags should have been checked in main()");
  };
  - Ok(Library::probe(&pkg_name).expect(&format!("Package {} is not found", pkg_name)))
  + let out = Library::probe(&pkg_name).expect(&format!("Package {} is not found", pkg_name));
  + eprintln!("=== OpenCV library configuration: {:#?}", out);
  + Ok(out)
  }
  fn link_wrapper(opencv: &Library) -> Result<()> {
  