rc4.c: include md5.h for MD5_DIGEST_LENGTH

rc4.c uses MD5_DIGEST_LENGTH but doesn't include md5.h.  This change
adds the include <openssl/md5.h>.
vms-helper.c: fix default int warning
speed.c, version.c: include comp.h, fix implicit func warning
remove old build system
add include/openssl/opensslconf.h

This is eventually going to have to be generated by configure
add autotools build system