ClangTools: Add support for yaml-cpp 0.8

They renamed their target from `yaml-cpp`
to `yaml-cpp::yaml-cpp`

Still support < 0.8 though.

Fixes: QTCREATORBUG-29537
Change-Id: Iafa6e75998f0120610542b4c744b205aee3392a3

Index: cmake/Findyaml-cpp.cmake
--- cmake/Findyaml-cpp.cmake.orig
+++ cmake/Findyaml-cpp.cmake
@@ -15,7 +15,15 @@ if (yaml-cpp_FOUND)
     unset(yaml_cpp_include_dir CACHE)
     find_path(yaml_cpp_include_dir yaml-cpp/yaml.h)
   endif()
-  set_target_properties(yaml-cpp PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${yaml_cpp_include_dir}")
+  if(TARGET yaml-cpp::yaml-cpp)
+    # yaml-cpp >= 0.8
+    set_property(TARGET yaml-cpp::yaml-cpp PROPERTY IMPORTED_GLOBAL TRUE)
+    add_library(yaml-cpp ALIAS yaml-cpp::yaml-cpp)
+    set(yaml-cpp_TARGET yaml-cpp::yaml-cpp)
+  else()
+    set(yaml-cpp_TARGET yaml-cpp)
+  endif()
+  set_target_properties(${yaml-cpp_TARGET} PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${yaml_cpp_include_dir}")
 else()
   if(TARGET yaml-cpp)
     return()