add label and goto primitives to C code generation
add label and goto primitives to C code generation

darcs-hash:20060815054439-1a7c6-dd207515b22f5ba7ff5987cd6d8db6688256b6f8

kirbyfan64/jhc,kirbyfan64/jhc,kirbyfan64/jhc,kirbyfan64/jhc