diff --git a/Rakefile b/Rakefile
index cfd4181d7e09b1666b9731d56f1e849a4200151a..c8bca20ad1de671f5a65c5342097da1df4ffc478 100755
--- a/Rakefile
+++ b/Rakefile
@@ -5,6 +5,8 @@ require 'rubocop/rake_task'
 require 'bundler/gem_tasks'
 require 'fileutils'
 
+require_relative 'build_config.rb'
+
 load 'tools/distrib/docker_for_windows.rb'
 
 # Add rubocop style checking tasks
@@ -83,7 +85,7 @@ task 'dlls' do
   env += 'EMBED_ZLIB=true '
   env += 'BUILDDIR=/tmp '
   env += "V=#{verbose} "
-  out = '/tmp/libs/opt/grpc-1.dll'
+  out = GrpcBuildConfig::CORE_WINDOWS_DLL
 
   w64 = { cross: 'x86_64-w64-mingw32', out: 'grpc_c.64.ruby' }
   w32 = { cross: 'i686-w64-mingw32', out: 'grpc_c.32.ruby' }
diff --git a/build_config.rb b/build_config.rb
new file mode 100644
index 0000000000000000000000000000000000000000..35e887ef621fa52106c348614cd7c8013d3cd077
--- /dev/null
+++ b/build_config.rb
@@ -0,0 +1,32 @@
+# Copyright 2017, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+module GrpcBuildConfig
+  CORE_WINDOWS_DLL = '/tmp/libs/opt/grpc-2.dll'
+end
diff --git a/src/core/ext/census/tracing.c b/src/core/ext/census/tracing.c
index 3b5d6dab2b8d775f1624e5f922f9f692e66b98ea..9371fffc8d75392984bdbbdd194e4b82bee79716 100644
--- a/src/core/ext/census/tracing.c
+++ b/src/core/ext/census/tracing.c
@@ -31,15 +31,21 @@
  *
  */
 
+//#include "src/core/ext/census/tracing.h"
+
 #include <grpc/census.h>
+#include <stdlib.h>
 
 /* TODO(aveitch): These are all placeholder implementations. */
 
 int census_trace_mask(const census_context *context) {
+  abort();
   return CENSUS_TRACE_MASK_NONE;
 }
 
-void census_set_trace_mask(int trace_mask) {}
+void census_set_trace_mask(int trace_mask) { abort(); }
 
 void census_trace_print(census_context *context, uint32_t type,
-                        const char *buffer, size_t n) {}
+                        const char *buffer, size_t n) {
+  abort();
+}
diff --git a/templates/build_config.rb.template b/templates/build_config.rb.template
new file mode 100644
index 0000000000000000000000000000000000000000..0d9191b1a0718fd14891cac54e64bff60f092977
--- /dev/null
+++ b/templates/build_config.rb.template
@@ -0,0 +1,34 @@
+%YAML 1.2
+--- |
+  # Copyright 2017, Google Inc.
+  # All rights reserved.
+  #
+  # Redistribution and use in source and binary forms, with or without
+  # modification, are permitted provided that the following conditions are
+  # met:
+  #
+  #     * Redistributions of source code must retain the above copyright
+  # notice, this list of conditions and the following disclaimer.
+  #     * Redistributions in binary form must reproduce the above
+  # copyright notice, this list of conditions and the following disclaimer
+  # in the documentation and/or other materials provided with the
+  # distribution.
+  #     * Neither the name of Google Inc. nor the names of its
+  # contributors may be used to endorse or promote products derived from
+  # this software without specific prior written permission.
+  #
+  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+  # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+  # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+  # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+  # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+  # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+  module GrpcBuildConfig
+    CORE_WINDOWS_DLL = '/tmp/libs/opt/grpc-${settings.core_version.major}.dll'
+  end