You may come across this error in newer version of apache which is because the newer configurations use an event based Multi Processing Module by default. If the PHP is not compiled with threadsafe, you will need to switch to the prefork MPM, which does not use threads.

Apache is running a threaded MPM, but your PHP Module is not compiled to be threadsafe.  You need to recompile PHP.
 AH00013: Pre-configuration failed
httpd.service: control process exited, code=exited status=1

Look for the following in the Load Modules sections of your apache configuration file :

LoadModule mpm_event_module modules/

And replace it with the following module :

LoadModule mpm_prefork_module modules/