Conditionally parse documentation comments in system headers by
passing -fretain-comments-from-system-headers.  By default, the
compiler no longer parses such documentation comments, as they
can result in a noticeable compile time/PCH slowdown.

Fixes <rdar://problem/11860820>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163778 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed