(I'm the upstream gcc author of -Wmisleading-indentation) The code in question seems to be here:
https://hg.mozilla.org/projects/nss/file/tip/lib/dbm/src/h_page.c#l117 and contains mixed spaces and tabs. Detabifying at 8-spaces per tab (though am not sure if this is what upstream nss use), I get: if(origin == SEEK_CUR) { if(offset < 1) return(lseek(fd, offset, SEEK_CUR)); cur_pos = lseek(fd, 0, SEEK_CUR); if(cur_pos < 0) return(cur_pos); } IMHO the indentation here *is* misleading and hence the warning is justified. Hope this is constructive.