NEEDBYTE
#define NEEDBYTE {if(z->avail_in==0)goto empty;r=Z_OK;}
#undef NEEDBYTE
#define NEEDBYTE {if(n)r=Z_OK;else LEAVE}
#define NEEDBYTE {if (z->avail_in == 0) goto empty; r = Z_OK; } ((void)0)
#undef NEEDBYTE
#define NEEDBYTE { if (n) r = Z_OK; else LEAVE }