Make sure that c-index-test links as a C++ executable

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@83335 91177308-0d34-0410-b5e6-96231b3b80d8

tools/c-index-test/CMakeLists.txt

@@ -18,3 +18,8 @@ set( LLVM_LINK_COMPONENTS
 add_clang_executable(c-index-test
   c-index-test.c
   )
+
+set_target_properties(c-index-test
+  PROPERTIES
+  LINKER_LANGUAGE CXX)
+