MSVC provides __wchar_t. This is the same as the built-in wchar_t type
from C++, but it is also available with -fno-wchar and in C.
The commit changes ASTContext to have two different types for this:
- WCharTy is the built-in type used for wchar_t in C++ and __wchar_t.
- WideCharTy is the type of a wide character literal. In C++ this is
the same as WCharTy, and in C it is an integer type compatible with
the type in <stddef.h>.
This fixes PR15815.
llvm-svn: 181587
Hans Wennborg