libgd:
 * bump version to 2.1.0-rc2, contains fixes and improvements of libgd maintained by developers of php
 * required by php-5.5.x

php-5.3.x/5.4.x:
 * fix build problems with new libgd version


git-svn-id: file:///var/svn/freetz/trunk@10715 149334a1-2f27-0410-a3b9-fc62619ac1e6