gcc is getting smarter, so we need to hit it with a bigger stick
On x86_64 we are using C argument registers for global registers in
the STG machine. This is always going to be problematic when it comes
to making C calls from STG and compiling via C. Prior to GCC 4.1.0
(approx) it was possible to just assign the argument expressions to
temporaries to avoid a clash. Now, we need to add an extra dummy
function call as a barrier between the temporary assignments and the
actual call. The dummy call is removed by the mangler.