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; 
     }; 
```
unsigned int nBlockSize = ::GetSerializeSize(block, CLIENT_VERSION);
    FlatFilePos blockPos;
    if (dbp != nullptr)
        blockPos = *dbp;
    if (!FindBlockPos(blockPos, nBlockSize+8, nHeight, block.GetBlockTime(), dbp != nullptr)) {
        error("%s: FindBlockPos failed", __func__);
        return FlatFilePos();
    }
    if (dbp == nullptr) {
        if (!WriteBlockToDisk(block, blockPos, chainparams.MessageStart())) {
            AbortNode("Failed to write block");
            return FlatFilePos();
        }
    }
    return blockPos;
}
bool CChainState::AcceptBlock(const std::shared_ptr<const CBlock>& pblock, BlockValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex, bool fRequested, const FlatFilePos* dbp, bool* fNewBlock)
{
    const CBlock& block = *pblock;
    if (fNewBlock) *fNewBlock = false;
    AssertLockHeld(cs_main);
    CBlockIndex *pindexDummy = nullptr;
    CBlockIndex *&pindex = ppindex ? *ppindex : pindexDummy;
    bool accepted_header = m_blockman.AcceptBlockHeader(block, state, chainparams, &pindex);