(svn r14689) -Change: make configure die on commonly made user mistakes, like not having SDL development files or zlib headers installed; you can still compile a dedicated server or a binary without zlib, but you have to explicitly force it.

bin/lang/*
bin/opentd*
bundle/*
config.cache.*
config.log
config.pwd
Makefile
Makefile.am
media/openttd.desktop*
objs/*
src/rev.cpp