Find system jsoncpp via pkg-config, add system include

src/CMakeLists.txt

@@ -449,7 +449,7 @@ else()
 endif()
 
 if(WITH_SYSTEM_JSONCPP)
-  list(APPEND SMDATA_LINK_LIB ${JSONCPP_LIBRARY})
+  list(APPEND SMDATA_LINK_LIB ${JSONCPP_LIBRARIES})
 else()
   list(APPEND SMDATA_LINK_LIB "jsoncpp")
 endif()
@@ -617,7 +617,9 @@ if(NOT APPLE)
                 "${SM_EXTERN_DIR}/glew-1.5.8/include")
   endif()
 
-  if(NOT WITH_SYSTEM_JSONCPP)
+  if(WITH_SYSTEM_JSONCPP)
+    list(APPEND SM_INCLUDE_DIRS ${JSONCPP_INCLUDE_DIRS})
+  else()
     list(APPEND SM_INCLUDE_DIRS
                 "${SM_EXTERN_DIR}/jsoncpp/include")
   endif()