* ext/openssl/ossl_asn1.h: add OpenSSL::ASN1 module.
* ext/openssl/ossl.c (Init_openssl): call Init_ossl_asn1.
* ext/openssl/ossl.h: include ossl_asn1.h.
* ext/openssl/extconf.rb: check if X509_ATTRIBUTE has field "single".
* ext/openssl/ossl_x509attr.c (ossl_x509attr_set_value): accept
DER encoded data argument.
* ext/openssl/ossl_x509attr.c (ossl_x509attr_get_value): return
DER encoded data in OpenSSL::ASN1 types.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4660 b2dd03c8-39d4-4d8f-98ff-823fe69b080e