harness.c: In function 'main':
harness.c:369:12: warning: value computed is not used [-Wunused-value]
      errno == EEXIST;
            ^
harness.c:418:12: warning: value computed is not used [-Wunused-value]
      errno == EEXIST;
            ^
harness.c: In function 'nvextendbuf.constprop':
harness.c:180:16: warning: array subscript -1 is below array bounds of 'struct <anonymous>[4]' [-Warray-bounds]
   if (!dnp->blk[i].valid) {
        ~~~~~~~~^~~
harness.c:181:12: warning: array subscript -1 is below array bounds of 'struct <anonymous>[4]' [-Warray-bounds]
    dnp->blk[i].valid = 1;
    ~~~~~~~~^~~
harness.c:182:12: warning: array subscript -1 is below array bounds of 'struct <anonymous>[4]' [-Warray-bounds]
    dnp->blk[i].dirty = 0;
    ~~~~~~~~^~~
harness.c:183:22: warning: array subscript -1 is below array bounds of 'struct <anonymous>[4]' [-Warray-bounds]
    memset(dnp->blk[i].data, 0, BSIZE);
           ~~~~~~~~~~~^~~~~
build OK: ./harness