Teach CMake to put the CIndex header into the Xcode/MSVC project

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@96566 91177308-0d34-0410-b5e6-96231b3b80d8

tools/CIndex/CMakeLists.txt

@@ -26,6 +26,7 @@ add_clang_library(CIndex
   CIndexUSRs.cpp
   CIndexer.cpp
   CXCursor.cpp
+  ../../include/clang-c/Index.h
 )
 
 if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")