Fix bug in the alignment of comments.

Before:
const char *test[] = {
  // A
  "aaaa",
               // B
  "aaaaa",
};

After:
const char *test[] = {
  // A
  "aaaa",
  // B
  "aaaaa",
};

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174549 91177308-0d34-0410-b5e6-96231b3b80d8
Detect when we end up trying to load conflicting module files.

This can happen when one abuses precompiled headers by passing more -D
options when using a precompiled hedaer than when it was built. This
is intentionally permitted by precompiled headers (and is exploited by
some build environments), but causes problems for modules.

First part of <rdar://problem/13165109>, detecting when something when
horribly wrong.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174554 91177308-0d34-0410-b5e6-96231b3b80d8