SSL_OP_NO_TLSv1_2 is not supported by all openssl versions

hphp/runtime/base/util/curl_tls_workarounds.cpp

@@ -25,8 +25,13 @@ namespace HPHP {
 CURLcode curl_tls_workarounds_cb(CURL *curl, void *sslctx, void *parm) {
   // Check to see if workarounds are enabled.
   if (RuntimeOption::TLSDisableTLS1_2) {
+#ifdef SSL_OP_NO_TLSv1_2
     SSL_CTX* ctx = (SSL_CTX*)sslctx;
     SSL_CTX_set_options(ctx, SSL_CTX_get_options (ctx) | SSL_OP_NO_TLSv1_2);
+#else
+    raise_notice("TLSDisableTLS1_2 enabled, but this version of "
+                 "SSL does not support that option");
+#endif
   }
   return CURLE_OK;
 }