diff -urNpa proftpd-1.3.6.orig/include/log.h proftpd-1.3.6/include/log.h
--- proftpd-1.3.6.orig/include/log.h	2017-04-10 02:31:02.000000000 +0000
+++ proftpd-1.3.6/include/log.h	2017-12-30 22:55:37.846931027 +0000
@@ -31,6 +31,7 @@
 #ifndef PR_LOG_H
 #define PR_LOG_H
 
+#undef LOG_AUTHPRIV
 #ifndef LOG_AUTHPRIV
 #define LOG_AUTHPRIV LOG_AUTH
 #endif