in v0.12 https://github.com/bitcoin/bitcoin/pull/7081 (by @luke-jr) was merged adding `-bytespersigop` (with default of 20).

this is preventing simple bare multisig transactions from being accepted into mempool when the size is < 400 bytes.  
eg; https://gist.github.com/rubensayshi/ac4f617207f7a50559e85d61c05800be

from 1-of-7 and onwards they are accepted because the ratio of bytes:sigops is high enough.  
also having 2 or more inputs will work because it again tips the ratio of bytes:sigops over.

the reason mainly being that `GetLegacySigOpCount` calls `GetSigOpCount` with `fAccurate=false`.

It looks like changing `GetLegacySigOpCount` to use `fAccurate=true` would cause side effects in the few other places (`ConnectBlock`, `CheckBlock`, `CreateNewBlock`) and simply adding `fAccurate` as arg to `GetLegacySigOpCount` would affect the value stored in `CTxMemPoolEntry.sigOpCount` which in turn affects a bunch of other things.

#if ENABLE_ZMQ
static CZMQNotificationInterface* pzmqNotificationInterface = NULL;
#endif
#ifdef WIN32
#define MIN_CORE_FILEDESCRIPTORS 0
#else
#define MIN_CORE_FILEDESCRIPTORS 150
#endif
enum BindFlags {
    BF_NONE         = 0,
    BF_EXPLICIT     = (1U << 0),
    BF_REPORT_ERROR = (1U << 1),
    BF_WHITELIST    = (1U << 2),
};
static const char* FEE_ESTIMATES_FILENAME="fee_estimates.dat";
std::atomic<bool> fRequestShutdown(false);
void StartShutdown()
{
    fRequestShutdown = true;
}
bool ShutdownRequested()
{
    return fRequestShutdown;
}
/**
 * This is a minimally invasive approach to shutdown on LevelDB read errors from the
 * chainstate, while keeping user interface out of the common library, which is shared
 * between bitcoind, and bitcoin-qt and non-server tools.
*/
class CCoinsViewErrorCatcher : public CCoinsViewBacked