add checks for dtls functions only in openssl 1.0.1 and later

configure.in

@@ -941,6 +941,8 @@ SAC_OPENSSL
 if test x$HAVE_OPENSSL = x1; then
 	openssl_CFLAGS="$openssl_CFLAGS -DHAVE_OPENSSL";
 	APR_ADDTO(SWITCH_AM_CFLAGS, -DHAVE_OPENSSL)
+	AC_CHECK_LIB(ssl, SSL_CTX_set_tlsext_use_srtp, AC_DEFINE_UNQUOTED(HAVE_OPENSSL_DTLS_SRTP, 1, HAVE_OPENSSL_DTLS_SRTP))
+	AC_CHECK_LIB(ssl, DTLSv1_method, AC_DEFINE_UNQUOTED(HAVE_OPENSSL_DTLS, 1, HAVE_OPENSSL_DTLS))
 fi
 
 AX_CHECK_JAVA