This package just adds `fastHadd` program to the path. The program 
itself has to installed from CMSDIST: 
https://github.com/cms-sw/cmsdist/blob/IB/CMSSW_11_3_X/master/fasthadd.spec 
(backport clanup changes from cc8 branch). We need two script files and 
a spec.

These scripts that will be installed into the target machines. They find 
the tool that is being installed.

Files:
hadd
fasthadd-wrapper.spec
build.sh
README
VERSION_MAP

Bump the version up each time! Building will be done in /tmp area.

Build:

./build.sh

Package will be here: `/tmp/$USER/fasthadd/RPMS/x86_64/`
Copy to (any) P5 machine (for DQM):

`scp -o ProxyCommand="ssh cmsusr.cern.ch nc fu-c2f11-15-03.cms 22" 
~/tmp/${USER}RPMS/x86_64/fasthadd-13.0-1.x86_64.rpm 
fu-c2f11-15-03.cms:/nfshome0/${USER}/`

Intall on P5 machine:

`sudo yum install|localinstall fasthadd-13.0-1.x86_64.rpm`

`hadd` part of the package is used on P5 BUs to merge per run ROOT files 
from multiple FUs before uploading a single file to the DQM GUI.

Consult VERSION_MAP file on which corresponding cmsdist fasthadd and ROOT versions to install.
Only one version per machine is sufficient to install from the given list,
preference should normally be given to version related to the most recent CMSSW and ROOT version.