[CMake] One more try to make CMake clean up after itself

Seriously... CMake... You're on my list...

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@259873 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -586,6 +586,10 @@ if( CLANG_INCLUDE_DOCS )
   add_subdirectory(docs)
 endif()
 
+if(EXISTS "${CMAKE_CURRENT_BINARY_DIR}/clang.order")
+  file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/clang.order")
+endif()
+
 if(CLANG_ORDER_FILE STREQUAL "${CMAKE_CURRENT_BINARY_DIR}/clang.order")
   unset(CLANG_ORDER_FILE CACHE)
   unset(CLANG_ORDER_FILE)

tools/driver/CMakeLists.txt

@@ -87,7 +87,7 @@ if (APPLE)
   set(TOOL_INFO_BUILD_VERSION)
 endif()
 
-if(CLANG_ORDER_FILE)
+if(CLANG_ORDER_FILE AND EXISTS CLANG_ORDER_FILE)
   target_link_libraries(clang "-Wl,-order_file,${CLANG_ORDER_FILE}")
 endif()