CI review

build.rs

@@ -70,6 +70,21 @@ fn main() {
         }
         if !success {
             println!("'Visual Studio 17 2022' not found, trying 'Visual Studio 16 2019'");
+
+            // Remove all files (contents) from 'build_dir', but not 'build_dir' itself
+            if let Ok(dir_list) = fs::read_dir(build_dir) {
+                for entry in dir_list {
+                    if let Ok(entry) = entry {
+                        let path = entry.path();
+                        if path.is_file() {
+                            let _unused = fs::remove_file(path);
+                        } else if path.is_dir() {
+                            let _unused = fs::remove_dir_all(path);
+                        }
+                    }
+                }
+            }
+
             match Command::new("cmake")
                 .arg("-G")
                 .arg("Visual Studio 16 2019")