https://bugs.gentoo.org/935271
Backport proposed by upstream at https://marc.info/?l=oss-security&m=171982317624594&w=2.
--- a/log.c
+++ b/log.c
@@ -451,12 +451,14 @@ void
 sshsigdie(const char *file, const char *func, int line, int showfunc,
     LogLevel level, const char *suffix, const char *fmt, ...)
 {
+#ifdef SYSLOG_R_SAFE_IN_SIGHAND
 	va_list args;
 
 	va_start(args, fmt);
 	sshlogv(file, func, line, showfunc, SYSLOG_LEVEL_FATAL,
 	    suffix, fmt, args);
 	va_end(args);
+#endif
 	_exit(1);
 }
 
