Do Not Merge:build: Workaround for race condition

See-Also: RIOT-OS/riotdocker#242

build.rs

@@ -185,6 +185,22 @@ fn main() {
         })
         .collect();
 
+    // Debug helper for https://github.com/RIOT-OS/riotdocker/issues/242
+    let preprocessor_include = cflags.iter().filter_map(|f| f.strip_prefix("-I")).filter(|f| f.ends_with("/preprocessor")).next();
+    if let Some(preprocessor_include) = preprocessor_include {
+        let filename = format!("{}/preprocessor_successor.h", preprocessor_include);
+        let mut countdown: usize = 10;
+        loop {
+            if std::path::PathBuf::from(&filename).exists() {
+                break;
+            }
+            countdown = countdown.checked_sub(1).unwrap_or_else(|| {
+                panic!("Preprocessor include path {} was present but preprocessor_successor.h did not show up there after 20 seconds", filename);
+            });
+            std::thread::sleep(std::time::Duration::from_secs(2));
+        }
+    }
+
     let bindings = builder()
         .header("riot-bindgen.h")
         .clang_args(&cflags)