autoconf: use AC_CONFIG_COMMANDS instead of ad-hoc 'config.mak.append' This will allow "./config.status --recheck; ./config.status" to work correctly as a mean of reconfiguring the tree with the same configure argument used in the previous "./configure" invocation. Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>