Unable to locate src files required for recompiling of apache in order to host more then 900 domains The recommendation to recompile apache was taken from this article:
Modern Plesk versions include modern Apache version, so it is not required to recompile apache in order to host more then 900 sites. It already allows doing so
If a lot number of domains should be hosted on a Plesk server, hardware requirements should be met according to the number of sites. For example, we recommend having 1GB of RAM for every 40-50 websites.