Usage of Debian’s php5enmod module doesn’t seem to be documented anywhere except from the command line when calling it without any arguments:
usage: php5enmod [ -s ALL|sapi_name ] module_name [ module_name_2 ]
Unfortunately, that provides no information on how to customize the priority of a module when enabling it. Some others seem to think that you should be able to provide a priority level on the command line, but that doesn’t work.
It took some digging into the bash scripts to figure out how to make it work. The trick is to add a comment in the .ini file for the module. The comment must contain a very specific format of:
zend_extension = /usr/lib/php5/20121212/ioncube_loader_lin_5.5.so
The ‘priority’ line must be in that format exactly and most not contain any other spaces or characters. The line must start with a semicolon, followed by a space, followed by priority=, and finally the desired priority level. The only space on the line must be between the semicolon and the word ‘priority’.