#define CH_NOQFROM (1<<15) /* ignore ">From " line */
#define CH_UPDATE_IRT (1<<16) /* update In-Reply-To: */
#define CH_UPDATE_REFS (1<<17) /* update References: */
+#define CH_DISPLAY (1<<18) /* display result to user */
int mutt_copy_hdr (FILE *, FILE *, LOFF_T, LOFF_T, int, const char *);