remove Makefile only for BSD.
ignore autoconf cache files.
add initial files for autoconf tools.
generate files by autoconf tools.
ignore files that configuring scripts generate.
include config.h.
compile proper files.
check rump header files.
regen.
introduce a header file, ping.h, in order to locate platform dependent
definitions.
check more header file.
check more header file.
add missing definition of macro.
check to see if struct sockaddr_in has a member, sin_len.
set sin_len if and only if struct sockaddr_in has a member, sin_len.
check to see if clock_gettime() exists or not.
include more generic header file, time.h, rather than sys/time.h.
 set sin_len if and only if struct sockaddr_in has a member, sin_len.
properly define HAVE_KCN.
check to see more header file.