Thanks to John Cummings.

src/cmd/upas/ml/dat.h

@@ -0,0 +1,25 @@
+
+#include "../smtp/smtp.h"
+#include "../smtp/y.tab.h"
+
+typedef struct Addr Addr;
+struct Addr
+{
+	char *addr;
+	Addr *next;
+};
+
+String *from;
+String *sender;
+Field *firstfield;
+int na;
+Addr *al;
+
+extern String*	getaddr(Node *p);
+extern void	getaddrs(void);
+extern void	writeaddr(char *file, char *addr, int, char *);
+extern void	remaddr(char *addr);
+extern int	addaddr(char *addr);
+extern void	readaddrs(char *file);
+extern int	startmailer(char *name);
+extern void	sendnotification(char *addr, char *listname, int rem);