compiler: Use backend interface for initialization functions.
	* go-gcc.cc (Gcc_backend::temporary_variable): Push cfun around
	call to create_tmp_var.  Require that function be non-NULL.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@209665 138bc75d-0d04-0410-961f-82ee72b054a4