struct block * compiler_add_ifblk ( struct ifblock * ifb , struct block * blk ) {
 struct block * bl ;
 SAFE_CALLOC ( bl , 1 , sizeof ( struct block ) ) ;
 bl -> type = BLK_IFBLK ;
 bl -> un . ifb = ifb ;
 bl -> next = blk ;
 return bl ;
 }
struct block * compiler_add_ifblk ( struct ifblock * ifb , struct block * blk ) {
 struct block * bl ;
 SAFE_CALLOC ( bl , 1 , sizeof ( struct block ) ) ;
 bl -> type = BLK_IFBLK ;
 bl -> un . ifb = ifb ;
 bl -> next = blk ;
 return bl ;
 }