-Fix [FS#6041]: Support save/load chunk lengths of up to (1 << 32) - 1

git-svn-id: http://svn.openttd.org/trunk@26650 6aa0318a-3be1-0310-93fa-89fd2396df07
-Fix: make sure an abs is used that supports int64 when using abs on those variables


git-svn-id: http://svn.openttd.org/trunk@26651 6aa0318a-3be1-0310-93fa-89fd2396df07
-Fix (r26482): Header file missing from sources.list.

git-svn-id: http://svn.openttd.org/trunk@26654 6aa0318a-3be1-0310-93fa-89fd2396df07