fixes for libmix:
	o had to move DELETE -> DEL because DELETE is already defined by other
	  header files such as the <arpa/nameser_compat.h> which breaks the
	  compilation of phatcat.
	o libtest needs to be linked against libmixnc and not libmix.
	o include <stdarg.h> in misc.c because the configure script doesn't
	  detect it. Grmpf!
