fix gcc 5.4 warnings

Jan Willamowius

2019-04-22 51213b102296c1e48f25aa9472a8be74a31cb6b7

 src/library/pc-identifiers.c

@@ -179,7 +179,7 @@
      if (use_label) {
         if (diskInfos[i].label[0] != 0) {
            memset(identifiers[j], 0, sizeof(PcIdentifier)); //!!!!!!!
            strncpy(identifiers[j], diskInfos[i].label,
            strncpy((char*)identifiers[j], diskInfos[i].label,
                  sizeof(PcIdentifier));
            j++;
         }