Edit the /usr/local/directadmin/custombuild/configure/ap2/configure.php70 file :
nano /usr/local/directadmin/custombuild/configure/ap2/configure.php70
....
--enable-mbstring \
--enable-soap \
....
Add:
--with-pdo-mysql=mysqlnd
at the end of the file. Do not forget to add '\' at the end of next to last line of the file.
Save the file.
Run:
cd /usr/local/directadmin/custombuild
./build php n
Once finished, check if PDO support is enabled:
#php -i | grep -i "PDO support"
You should receive an output like this:
PDO support => enabled