message: Interpret CARGO_TARGET_DIR as target/ if its '' with spaces trimmed
diff: @@ -450,6 +450,10 @@ impl Config {
  if let Some(dir) = &self.target_dir {
  Ok(Some(dir.clone()))
  } else if let Some(dir) = env::var_os("CARGO_TARGET_DIR") {
  + if dir.to_str().unwrap().trim() == "" {
  + return Ok(Some(Filesystem::new(self.cwd.join("target"))));
  + }
  +
  Ok(Some(Filesystem::new(self.cwd.join(dir))))
  } else if let Some(val) = &self.build_config()?.target_dir {
  let val = val.resolve_path(self);
  