CiviMail doesn't work with PHP 4, so doesn't have to be shipped in the PHP 4 tarballs.
Since 1.8 is the last PHP4 release its not worth spending time or energy testing and debugging this
What would you say for the following patch instead? (It's trivial, perhaps it could even be backported to 1.7?)
The proposed 'No CiviMail in PHP 4' patch.
Fixed in r9554.
confirmed : distmaker.sh creates only joomla-php5 and drupal-php5 tarballs
Verify for 2.0
Verified and Confirm for 2.0 ( r -12840 )
Since 1.8 is the last PHP4 release its not worth spending time or energy testing and debugging this