--- dialects/freebsd/dlsof.h.orig	2019-10-07 18:51:07.005863000 +0200
+++ dialects/freebsd/dlsof.h	2019-10-07 18:51:56.965235000 +0200
@@ -44,6 +44,7 @@
 #include <setjmp.h>
 #include <signal.h>
 #include <unistd.h>
+#include <stddef.h>
 
 #if    FREEBSDV>=13000
 /* This header is a huge mess.  Please don't support EOL FreeBSD releases. */