Only in patched: build
diff -ura orig/rviz-release-release-ardent-rviz_yaml_cpp_vendor-2.0.0-5/rviz_yaml_cpp_vendor-extras.cmake.in patched/rviz-release-release-ardent-rviz_yaml_cpp_vendor-2.0.0-5/rviz_yaml_cpp_vendor-extras.cmake.in
--- orig/rviz-release-release-ardent-rviz_yaml_cpp_vendor-2.0.0-5/rviz_yaml_cpp_vendor-extras.cmake.in	2017-12-09 10:13:15.000000000 +0100
+++ patched/rviz-release-release-ardent-rviz_yaml_cpp_vendor-2.0.0-5/rviz_yaml_cpp_vendor-extras.cmake.in	2017-12-21 22:50:26.424578460 +0100
@@ -1,14 +1,10 @@
-find_package(yaml-cpp QUIET)
-
-if(NOT yaml-cpp_FOUND)
-  # add the local Modules directory to the modules path
-  if(WIN32)
-    set(yaml-cpp_DIR "${@PROJECT_NAME@_DIR}/../../../opt/rviz_yaml_cpp_vendor/CMake")
-  else()
-    set(yaml-cpp_DIR "${@PROJECT_NAME@_DIR}/../../../opt/rviz_yaml_cpp_vendor/lib/cmake/yaml-cpp")
-  endif()
-  message(STATUS "Setting yaml-cpp_DIR to: '${yaml-cpp_DIR}'")
+# add the local Modules directory to the modules path
+if(WIN32)
+  set(yaml-cpp_DIR "${@PROJECT_NAME@_DIR}/../../../opt/rviz_yaml_cpp_vendor/CMake")
+else()
+  set(yaml-cpp_DIR "${@PROJECT_NAME@_DIR}/../../../opt/rviz_yaml_cpp_vendor/lib/cmake/yaml-cpp")
 endif()
+message(STATUS "Setting yaml-cpp_DIR to: '${yaml-cpp_DIR}'")
 
 find_package(yaml-cpp CONFIG REQUIRED QUIET)