$NetBSD: patch-dl,v 1.1 2010/12/29 05:57:52 obache Exp $

--- mono/utils/dlmalloc.c.orig	2010-11-12 10:24:41.000000000 +0000
+++ mono/utils/dlmalloc.c
@@ -1207,7 +1207,7 @@ int mspace_mallopt(int, int);
 #ifndef LACKS_UNISTD_H
 #include <unistd.h>     /* for sbrk */
 #else /* LACKS_UNISTD_H */
-#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
+#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) || !defined(__DragonFly__)
 extern void*     sbrk(ptrdiff_t);
 #endif /* FreeBSD etc */
 #endif /* LACKS_UNISTD_H */