Bug 30843

pkg_add don't understand -t flag
according man:
     -t template
             Use template as the input to mktemp(3) when creating a `staging
             area''.  By default, this is the string /var/tmp/instmp.XXXXXX,
             but it may be necessary to override it in the situation where
             space in your /var/tmp directory is limited.  Be sure to leave
             some number of  characters for mktemp(3) to fill in with a
             unique ID.
reading source src/usr.sbin/pkg_install/lib/pen.c:

find_play_pen(char *pen, size_t sz)
{
    char *cp;
    struct stat sb;

    if (pen[0] && stat(pen, &sb) != FAIL && (min_free(pen) >= sz))
----------------- ^^^^^^^^^^^^^^
        return pen;
    else if ((cp = getenv("PKG_TMPDIR")) != NULL && stat(cp, &sb) != FAIL && (min_free(cp) >= sz))
        sprintf(pen, "%s/instmp.XXXXXX", cp);
    else if ((cp = getenv("TMPDIR")) != NULL && stat(cp, &sb) != FAIL && (min_free(cp) >= sz))
        sprintf(pen, "%s/instmp.XXXXXX", cp);
    else if (stat("/var/tmp", &sb) != FAIL && min_free("/var/tmp") >= sz)
        strcpy(pen, "/var/tmp/instmp.XXXXXX");
    else if (stat("/tmp", &sb) != FAIL && min_free("/tmp") >= sz)
        strcpy(pen, "/tmp/instmp.XXXXXX");
    else if ((stat("/usr/tmp", &sb) == SUCCESS || mkdir("/usr/tmp", 01777) == SUCCESS) && min_free("/usr/tmp") >= sz)
        strcpy(pen, "/usr/tmp/instmp.XXXXXX");
    else {
        cleanup(0);

So, if we run "pkg_add -t /tmp/SOMEXXXXX.tmp package" pkg_add will check /tmp/SOMEXXXXX.tmp
for existance and then completly ignore -t parametr instead of create /tmp/SOME<UNIQNUM>.tmp directory

How-To-Repeat: 
  pkg_add -t /tmp/some-none-existant-dir-for-template.XXXXX <package>