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.

fstore_t fst;
    fst.fst_flags = F_ALLOCATECONTIG;
    fst.fst_posmode = F_PEOFPOSMODE;
    fst.fst_offset = 0;
    fst.fst_length = (off_t)offset + length;
    fst.fst_bytesalloc = 0;
    if (fcntl(fileno(file), F_PREALLOCATE, &fst) == -1) {
        fst.fst_flags = F_ALLOCATEALL;
        fcntl(fileno(file), F_PREALLOCATE, &fst);
    }
    ftruncate(fileno(file), fst.fst_length);
#elif defined(__linux__)
    
    off_t nEndPos = (off_t)offset + length;
    posix_fallocate(fileno(file), 0, nEndPos);
#else
    
    
    static const char buf[65536] = {};
    fseek(file, offset, SEEK_SET);
    while (length > 0) {
        unsigned int now = 65536;
        if (length < now)
            now = length;
        fwrite(buf, 1, now, file); 
        length -= now;
    }
#endif
}
void ShrinkDebugFile()