CIndex: initialise TU

TU is not guaranteed to be initialised in all cases.  In particular if CIdx or
ast_filename is NULL (or if &TU is NULL), then clang_createTranslationUnit2 will
not initialise the out parameter out_TU.  This is followed by an assertion check
which may perform a branch based on unitialised memory.

Caught by scan-build.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@201628 91177308-0d34-0410-b5e6-96231b3b80d8
Implement DR577

DR18 previously forebode typedefs to be used as parameter types if they
were of type 'void'.  DR577 allows 'void' to be used as a function
parameter type regardless from where it came.


git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@201631 91177308-0d34-0410-b5e6-96231b3b80d8
Regenerate DR status page.


git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@201632 91177308-0d34-0410-b5e6-96231b3b80d8
Remove gunk from cxx_dr_status.html

Accidentally piped the stdout from make_cxx_dr_status into
cxx_dr_status.html


git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@201634 91177308-0d34-0410-b5e6-96231b3b80d8
Add an OverlayFileSystem class

Provides a way to merge multiple vfs::FileSystem objects into a single
filesystem.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@201635 91177308-0d34-0410-b5e6-96231b3b80d8
Pass VFS from CompilerInstance to FileManager

This change was somehow missed from r201618

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@201636 91177308-0d34-0410-b5e6-96231b3b80d8