dispatch.c, kdc_util.h, kerberos_v4.c: Use KRB5_KRB4_COMPAT instead of

dispatch.c, kdc_util.h, kerberos_v4.c: Use KRB5_KRB4_COMPAT instead of
	KRB4 for determining whether to compile in Kerberos V4 backwards
	compatibility

configure.in: Remove standardized set of autoconf macros, which are
	now handled by CONFIG_RULES.

do_as_req.c, do_tgs_req.c, kdc_util.c, kerberos_v4.c, main.c,
	network.c: Fix -Wall nits.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@6016 dc483132-0cff-0310-8789-dd5450dbe970