Track the currently-being-built submodule inside the preprocessor (rather than
just storing a flag indicating if there was one), and include it in the 'end of
module' annotation. No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@200573 91177308-0d34-0410-b5e6-96231b3b80d8