QA output created by 958
expect only a few lines of diff output ...

--- xz first volume ---
> pmdumplog ...
>              Warning: file missing or compressed for log volume 0
> pminfo ...
> pmprobe in the middle ...
> pmval & pmval -r ...
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin
> pmie ...

--- xz last volume and use existing .9.xz in -a arg ---
> pmdumplog ...
>              Warning: file missing or compressed for log volume 9
> pminfo ...
> pmprobe in the middle ...
> pmval & pmval -r ...
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin.9.xz
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin.9.xz
> pmie ...

--- xz middle volume and used existing .1 in -a arg ---
> pmdumplog ...
>              Warning: file missing or compressed for log volume 5
> pminfo ...
> pmprobe in the middle ...
> pmval & pmval -r ...
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin.1
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin.1
> pmie ...

--- xz first, middle and last volume and use .meta in -a arg ---
> pmdumplog ...
>              Warning: file missing or compressed for log volume 0
>              Warning: file missing or compressed for log volume 5
>              Warning: file missing or compressed for log volume 9
> pminfo ...
> pmprobe in the middle ...
> pmval & pmval -r ...
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin.meta
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin.meta
> pmie ...

--- xz first few, middle and last few volumes and use existing .7.xz in -a arg ---
> pmdumplog ...
>              Warning: file missing or compressed for log volume 0
>              Warning: file missing or compressed for log volume 1
>              Warning: file missing or compressed for log volume 5
>              Warning: file missing or compressed for log volume 7
>              Warning: file missing or compressed for log volume 8
>              Warning: file missing or compressed for log volume 9
> pminfo ...
> pmprobe in the middle ...
> pmval & pmval -r ...
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin.7.xz
< archive:   tmparch/mv-bigbin
---
> archive:   mv-bigbin.7.xz
> pmie ...

--- some error cases ---
pminfo: Cannot open archive "mv-bigbin.10": No such file or directory
pmprobe: Cannot open archive "mv-bigbin.10": No such file or directory
pmval: Cannot open archive "mv-bigbin.10": No such file or directory
pmie: cannot open archive mv-bigbin.10
pmNewContext failed: No such file or directory
pminfo: Cannot open archive "mv-bigbin.10.xz": No such file or directory
pmprobe: Cannot open archive "mv-bigbin.10.xz": No such file or directory
pmval: Cannot open archive "mv-bigbin.10.xz": No such file or directory
pmie: cannot open archive mv-bigbin.10.xz
pmNewContext failed: No such file or directory
xz: ./null.0.xz: File format not recognized
pminfo: Cannot open archive "null": Corrupted record in a PCP archive log
