Add common linked list implementation Taken from xserver/include/list.h. The changes made are: * Drop the xorg_ prefix and some typedef from the end. * Rename _for_each_entry macros to just _foreach (like darray). * Rename list_is_empty to list_empty (like darray). * Add a list_replace function which we use later. Signed-off-by: Ran Benita <ran234@gmail.com>