PHP Notices when running makepot.php tool on a plugin

[jdgrimes]

When I run ~/tools/i18n/makepot.php on a plugin, I get a bunch of strict notices (PHP 5.5).

PHP Strict Standards:  Only variables should be passed by reference in /Users/johngrimes/svn/wordpress/trunk/tools/i18n/extract.php on line 31
PHP Strict Standards:  Only variables should be passed by reference in /Users/johngrimes/svn/wordpress/trunk/tools/i18n/extract.php on line 34
PHP Strict Standards:  Non-static method MakePOT::get_first_lines() should not be called statically, assuming $this from incompatible context in /Users/johngrimes/svn/wordpress/trunk/tools/i18n/pot-ext-meta.php on line 35
PHP Strict Standards:  Non-static method MakePOT::get_addon_header() should not be called statically, assuming $this from incompatible context in /Users/johngrimes/svn/wordpress/trunk/tools/i18n/pot-ext-meta.php on line 38
PHP Strict Standards:  Non-static method PO::export_entry() should not be called statically, assuming $this from incompatible context in /Users/johngrimes/svn/wordpress/trunk/tools/i18n/pot-ext-meta.php on line 45
PHP Strict Standards:  Non-static method PO::comment_block() should not be called statically, assuming $this from incompatible context in /Users/johngrimes/svn/wordpress/trunk/src/wp-includes/pomo/po.php on line 200
PHP Strict Standards:  Non-static method PO::prepend_each_line() should not be called statically, assuming $this from incompatible context in /Users/johngrimes/svn/wordpress/trunk/src/wp-includes/pomo/po.php on line 185
PHP Strict Standards:  Non-static method PO::poify() should not be called statically, assuming $this from incompatible context in /Users/johngrimes/svn/wordpress/trunk/src/wp-includes/pomo/po.php on line 204

[SergeyBiryukov]

In 29563:

Fix strict notices in makepot.

props jdgrimes.
fixes #29254.