Add -cipher option to bssl client.

Change-Id: I3da1af62de9a94317fa7f14fda00e230b32bf5d5
Reviewed-on: https://boringssl-review.googlesource.com/2081
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/tool/client.cc b/tool/client.cc
index d7d9e22..6cc93d6 100644
--- a/tool/client.cc
+++ b/tool/client.cc
@@ -47,6 +47,10 @@
      "The hostname and port of the server to connect to, e.g. foo.com:443",
     },
     {
+     "-cipher", false,
+     "An OpenSSL-style cipher suite string that configures the offered ciphers",
+    },
+    {
      "", false, "",
     },
 };
@@ -265,6 +269,10 @@
     SSL_CTX_set_keylog_bio(ctx, keylog_bio);
   }
 
+  if (args_map.count("-cipher") != 0) {
+    SSL_CTX_set_cipher_list(ctx, args_map["-cipher"].c_str());
+  }
+
   int sock = -1;
   if (!Connect(&sock, args_map["-connect"])) {
     return false;