Clang on Windows: Errors when concatenating __FUNCSIG__ with string literals

This also applies to other predefined string literals like __FUNCDNAME__ and __FUNCTION__. See Visual Studio 2015 - Predefined macros for more.

The following code generates an error diagnostic (on Windows/MSVC the __FUNCSIG__ might come from e.g. Q_FUNC_INFO, for example in combination with qDebug()):

void f()
{
    __FUNCSIG__ "foo"; // error: expected ';' after expression
}

For libclang 3.6.2 __FUNCSIG__ does not seem to be a predefined string literal (which can be written next to each other), but the name of a variable to a predefined variable).

This is a bug in libclang.