Add a cmake-file that can be included from Pico-SDK-based project to use jsoncpp as an interface library

Author: kripton

interfaceLibForPicoSDK.cmake

@@ -0,0 +1,17 @@
+## Include this file if you want to use the jsoncpp library
+## in YOUR (Pico) project.
+
+cmake_minimum_required(VERSION 3.12)
+
+# Define the jsoncpp library
+add_library(jsoncpp INTERFACE)
+
+target_sources(jsoncpp INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR}/src/lib_json/json_reader.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/lib_json/json_value.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/lib_json/json_writer.cpp
+)
+
+target_include_directories(jsoncpp INTERFACE
+    ${CMAKE_CURRENT_LIST_DIR}/include/
+)