For apptainer, move TMPDIR away from tmpfs

[afbjorklund]

It has some issues with it being mounted as "nodev", so revert to using a normal file system for $TMPDIR.

$ limactl shell singularity singularity run -u -B $HOME:$HOME docker://alpine
INFO:    Converting OCI blobs to SIF format
WARNING: 'nodev' mount option set on /tmp, it could be a source of failure during build process
INFO:    Starting build...
Getting image source signatures
Copying blob 213ec9aee27d done  
Copying config 29f453b10b done  
Writing manifest to image destination
Storing signatures
2022/10/02 07:18:41  info unpack layer: sha256:213ec9aee27d8be045c6a92b7eac22c9a64b44558193775a1a7f626352392b49
2022/10/02 07:18:41  warn xattr{etc/shadow} ignoring ENOTSUP on setxattr "user.rootlesscontainers"
2022/10/02 07:18:41  warn xattr{/tmp/build-temp-98011911/rootfs/etc/shadow} destination filesystem does not support xattrs, further warnings will be suppressed
INFO:    Creating SIF file...
INFO:    Converting SIF file to temporary sandbox...
Apptainer> 

Using /var/tmp is the recommended revert, from the Fedora instructions regarding the change (in fc18):

https://fedoraproject.org/wiki/Features/tmp-on-tmpfs

[anders@lima-singularity lima]$ df -h /var /tmp
Filesystem      Size  Used Avail Use% Mounted on
/dev/vda5        99G  708M   98G   1% /
tmpfs           2.0G     0  2.0G   0% /tmp
[anders@lima-singularity lima]$ findmnt /
TARGET SOURCE           FSTYPE OPTIONS
/      /dev/vda5[/root] btrfs  rw,relatime,seclabel,compress=zstd:1,space_cache=v2,subvolid=256,subvol=/root
[anders@lima-singularity lima]$ findmnt /tmp
TARGET SOURCE FSTYPE OPTIONS
/tmp   tmpfs  tmpfs  rw,nosuid,nodev,seclabel,nr_inodes=1048576,inode64

[afbjorklund]

This wasn't a problem in Enterprise Linux 8, since it had /tmp on a regular file system:

[anders@lima-apptainer lima]$ df -h /var /tmp
Filesystem      Size  Used Avail Use% Mounted on
/dev/vda1       100G  2.2G   98G   3% /
/dev/vda1       100G  2.2G   98G   3% /
[anders@lima-apptainer lima]$ findmnt /
TARGET SOURCE    FSTYPE OPTIONS
/      /dev/vda1 xfs    rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota

But it became one, when switching apptainer from Rocky Linux 8 to Fedora Linux 36.

[AkihiroSuda]

Needs rebase