add include/ruby/backward/cxxanyargs.hpp

Compilation of extension libraries written in C++ are reportedly
broken due to https://github.com/ruby/ruby/pull/2404

The root cause of this issue was that the definition of ANYARGS
differ between C and C++, and that of C++ is incompatible with the
updated ones.

We are using the incompatibility against itself.  In C++ two distinct
function prototypes can be overloaded.  We provide the old, ANYARGSed
prototypes in addition to the current granular ones; and let the
older ones warn about types.

0 files changed, 0 insertions, 0 deletions