extern void header_add_at_position(BOOL, uschar *, BOOL, int, char *, ...);
extern void header_remove(int, uschar *);
extern BOOL header_testname(header_line *, uschar *, int, BOOL);
extern void header_add_at_position(BOOL, uschar *, BOOL, int, char *, ...);
extern void header_remove(int, uschar *);
extern BOOL header_testname(header_line *, uschar *, int, BOOL);