File descriptor leaks on header files that contain errors

[JeanYves]

Summary

When using qtcreator, I remarked that there were some file descriptor leaks inside the clang lib.
On windows OS, it is quite annoying as some files cannot be saved.

I already posted a message on this matter earlier this year:
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20151123/143910.html

[erikjv]

That's actually working around the real problem, see https://reviews.llvm.org/D27810 . I'm also not sure if this is safe: if the memory buffer is mmap-backed, this could lead to some kind of use-after-free, because clang often uses StringRefs back into buffers in order to minimise string copies.

[milianw]

Can this be abandoned now that the issue Erik has mentioned got fixed?