Just noticed this during a full compile:
diff -r 6a8890df7092 rfc822.c
--- a/rfc822.c Sun Mar 13 12:50:49 2016 -0700
+++ b/rfc822.c Tue Apr 05 19:41:36 2016 -0700
@@ -416,7 +416,7 @@
#ifdef EXACT_ADDRESS
# define SET_P_BEGIN(a, v) do { if ((a)) { (a)->a_p_begin = (v); } } while (0)
#else
-# define SET_P_BEGIN(a)
+# define SET_P_BEGIN(a, v)
#endif
#define RFC822_NEW_ADDRESS(a) do { \
