Hadrian "resource busy" errors are more frequent

I have been getting rather many copyFile:atomicCopyFileContents:withReplacementFile:copyFileToHandle:openFile: resource busy (file is locked) errors in Hadrian when building GHC lately. I don't have a specific reproducer, but it seems it got worse in the past couple of months, as I now have to restart the build several times over to get through all of these errors.