I am having some issues with enabling the modules mentioned in the title on my CentOS machine.
yum install php-mcrypt / php-soap / php-mysql worked fine and mentioned that they had been installed, after restarting Apache it appears that they aren't enabled.
I cannot locate the mcrypt.so for example, and running php --ini gives:
PHP Warning: PHP Startup: Unable to load dynamic library './mcrypt.so' - ./mcrypt.so: cannot open shared object file: No such file or directory in Unknown on line 0
This is after I put extension=mcrypt.so in the php.ini.