Add build override for jsoncpp

build_overrides/jsoncpp.gni

@@ -0,0 +1,17 @@
+# Copyright (c) 2020 Project CHIP Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+declare_args() {
+  jsoncpp_root = "//third_party/jsoncpp"
+}

src/lib/support/jsontlv/BUILD.gn

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import("//build_overrides/chip.gni")
+import("//build_overrides/jsoncpp.gni")
 
 config("jsontlv_config") {
   cflags = [ "-Wno-implicit-fallthrough" ]
@@ -25,6 +26,6 @@ static_library("jsontlv") {
 
   public_deps = [
     "${chip_root}/src/lib/core",
-    "${chip_root}/third_party/jsoncpp",
+    jsoncpp_root,
   ]
 }