I'm getting the following during installation in either 2.4 or master. Haven't tried 2.3. Fred isnt able to reproduce this so something about my setup is a factor.

PHP Warning: Creating default object from empty value in /home/andrew/Desktop/code/moodle/int/master/lib/moodlelib.php on line 6470
PHP Stack trace:
PHP 1.
Unknown macro:

Unknown macro: {main}

() /home/andrew/Desktop/code/moodle/int/master/admin/cli/install.php:0
PHP 2. lang_installer->run() /home/andrew/Desktop/code/moodle/int/master/admin/cli/install.php:389
PHP 3. lang_installer->get_parent_language() /home/andrew/Desktop/code/moodle/int/master/lib/componentlib.class.php:643
PHP 4. get_parent_language() /home/andrew/Desktop/code/moodle/int/master/lib/componentlib.class.php:759

Warning: Creating default object from empty value in /home/andrew/Desktop/code/moodle/int/master/lib/moodlelib.php on line 6470

Call Stack:
0.0024 398400 1.

() /home/andrew/Desktop/code/moodle/int/master/admin/cli/install.php:0
297.6257 14811480 2. lang_installer->run() /home/andrew/Desktop/code/moodle/int/master/admin/cli/install.php:389
298.8165 14816264 3. lang_installer->get_parent_language() /home/andrew/Desktop/code/moodle/int/master/lib/componentlib.class.php:643
298.8165 14816296 4. get_parent_language() /home/andrew/Desktop/code/moodle/int/master/lib/componentlib.class.php:759

PHP Warning: Creating default object from empty value in /home/andrew/Desktop/code/moodle/int/master/lib/moodlelib.php on line 6471
PHP Stack trace:
PHP 1.
Unknown macro:

() /home/andrew/Desktop/code/moodle/int/master/admin/cli/install.php:0
PHP 2. lang_installer->run() /home/andrew/Desktop/code/moodle/int/master/admin/cli/install.php:389
PHP 3. lang_installer->get_parent_language() /home/andrew/Desktop/code/moodle/int/master/lib/componentlib.class.php:643
PHP 4. get_parent_language() /home/andrew/Desktop/code/moodle/int/master/lib/componentlib.class.php:759

Warning: Creating default object from empty value in /home/andrew/Desktop/code/moodle/int/master/lib/moodlelib.php on line 6471

Call Stack:
0.0024 398400 1.

() /home/andrew/Desktop/code/moodle/int/master/admin/cli/install.php:0
297.6257 14811480 2. lang_installer->run() /home/andrew/Desktop/code/moodle/int/master/admin/cli/install.php:389
298.8165 14816264 3. lang_installer->get_parent_language() /home/andrew/Desktop/code/moodle/int/master/lib/componentlib.class.php:643
298.8165 14816296 4. get_parent_language() /home/andrew/Desktop/code/moodle/int/master/lib/componentlib.class.php:759