missing autoconf_input files added
merge of '0c6206d09dbdce5c45dec6a3407e5cce5769aa27'
     and '353967305a6673601bc4d5c51488fe6015cb56c5'
tests/sautoconf_project: missing files added
merge of '1463ffacc605bbbbe2e9b9566dac8f4a65e5fad5'
     and '2c3b4dc57f326ca7f660f502fa71a4c9a8067cf6'
autoconf.mk: automatically distribute sources of autoconf generated files
distcheck target implemented (checks tar.gz distribution), no auto-tests yet
* test and install as default tests
* autoreconf & configure as default "pre-check-steps"