[CentOS] Apache HTTPD not picking up environment variables.

I'm trying to install DB2 on a CentOS 7 server. The problem I'm seeing is that the Apache httpd server fails to pick up the db2 environment variables. On an older version running under CentOS 5 this was done by inserting the following lines into the httpd start script in /etc/sysconfig/httpd:

if test -f /db2home/db2inst1/sqllib/db2profile; then . /db2home/db2inst1/sqllib/db2profile fi

Under CentOS 7's systemctl system this no longer works. I need a clue as to where to start looking for where to put this so it will be sourced when the Apache server starts. I have googled this and can find nothing relevant. I even did a "find / -name httpd -print" and didn't find anything looking promising.

Thanks for your help

Harold