https://github.com/bitcoin/bitcoin/blob/68f3c7eb080e461cfeac37f8db7034fe507241d0/src/prevector.h#L152-L158

I'm opening an issue as its fix is too tiny to become a pull request.

Can be solved by renaming the struct to
```c
     struct indirect_contents { 
         size_type capacity; 
         char* indirect; 
     }; 
```
{
    for (std::set<int>::iterator it = setFilesToPrune.begin(); it != setFilesToPrune.end(); ++it) {
        FlatFilePos pos(*it, 0);
        fs::remove(BlockFileSeq().FileName(pos));
        fs::remove(UndoFileSeq().FileName(pos));
        LogPrintf("Prune: %s deleted blk/rev (%05u)\n", __func__, *it);
    }
}
static void FindFilesToPruneManual(std::set<int>& setFilesToPrune, int nManualPruneHeight)
{
    assert(fPruneMode && nManualPruneHeight > 0);
    LOCK2(cs_main, cs_LastBlockFile);
    if (::ChainActive().Tip() == nullptr)
        return;
    
    unsigned int nLastBlockWeCanPrune = std::min((unsigned)nManualPruneHeight, ::ChainActive().Tip()->nHeight - MIN_BLOCKS_TO_KEEP);
    int count=0;
    for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
        if (vinfoBlockFile[fileNumber].nSize == 0 || vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune)
            continue;
        PruneOneBlockFile(fileNumber);
        setFilesToPrune.insert(fileNumber);
        count++;
    }
    LogPrintf("Prune (Manual): prune_height=%d removed %d blk/rev pairs\n", nLastBlockWeCanPrune, count);
}
void PruneBlockFilesManual(int nManualPruneHeight)