diff -up pnm2ppa-1.13/ppa_syslog.h.gcc10 pnm2ppa-1.13/ppa_syslog.h
--- pnm2ppa-1.13/ppa_syslog.h.gcc10	2023-10-20 14:27:00.381590872 +0200
+++ pnm2ppa-1.13/ppa_syslog.h	2023-10-20 14:27:10.052671328 +0200
@@ -39,7 +39,7 @@
 #include <syslog.h>
 #endif
 
-char syslog_message[128];
+extern char syslog_message[128];
 extern size_t message_size ;
 
 void wrap_syslog( int, char *, char *);
diff -up pnm2ppa-1.13/syslog.c.gcc10 pnm2ppa-1.13/syslog.c
--- pnm2ppa-1.13/syslog.c.gcc10	2023-10-20 14:23:10.093285301 +0200
+++ pnm2ppa-1.13/syslog.c	2023-10-20 14:26:04.925129503 +0200
@@ -33,6 +33,8 @@
 
 BOOLEAN verbose = false ;
 
+char syslog_message[128];
+
 /*
   For some reason, BeOS doesn't seem to implement syslog(), even though it is
   included with the system.  Wierd.  This wraps the syslog functions used