The variables "[fReopenDebugLog](https://github.com/bitcoin/bitcoin/blob/fa24439ff3d8ab5b9efaf66ef4dae6713b88cb35/src/util.h#L53)" and "[fRequestShutdown](https://github.com/bitcoin/bitcoin/blob/fae78fa81802b5387054715c339f286ef436408e/src/init.cpp#L128)" should [use the data type "sig_atomic_t"](https://www.securecoding.cert.org/confluence/display/c/SIG31-C.+Do+not+access+shared+objects+in+signal+handlers) (instead of "bool").

I reported this issue for [another evolving software](https://github.com/Electric-Coin-Company/zcash/issues/678) before.

{
    int ret = 0; 
    static bool fStartedNewLine = true;
    string strTimestamped = LogTimestampStr(str, &fStartedNewLine);
    if (fPrintToConsole)
    {
        
        ret = fwrite(strTimestamped.data(), 1, strTimestamped.size(), stdout);
        fflush(stdout);
    }
    else if (fPrintToDebugLog)
    {
        boost::call_once(&DebugPrintInit, debugPrintInitFlag);
        boost::mutex::scoped_lock scoped_lock(*mutexDebugLog);
        
        if (fileout == NULL) {
            assert(vMsgsBeforeOpenLog);
            ret = strTimestamped.length();
            vMsgsBeforeOpenLog->push_back(strTimestamped);