alloca and labels as values

[Marc Nieper-Wißkirchen]

Hi,

let me first say that libgccjit is a great project and that I like the 
API very much!

Is `alloca' currently possible with libgccjit? I haven't found anything 
about it in the documentation. If it isn't possible at the moment, I'd 
love to see it added to libgccjit very soon. (One use case would be a 
compiler like the Chicken Scheme compiler that employs Cheney-on-the-MTA 
where the youngest heap generation is allocated on the stack.)

Another thing that may be missing is label values as implemented by the 
GCC C/C++ frontends.

Thanks!

Marc