--- filter/tree.c
+++ filter/tree.c
@@ -6,6 +6,8 @@
  *	Can be freely distributed and used under the terms of the GNU GPL.
  */
 
+#include <stdlib.h> /* qsort */
+
 #include "lib/alloca.h"
 #include "nest/bird.h"
 #include "conf/conf.h"
--- lib/alloca.h
+++ lib/alloca.h
@@ -9,6 +9,8 @@
 #ifndef _BIRD_ALLOCA_H_
 #define _BIRD_ALLOCA_H_
 
+#include "nest/bird.h" /* HAVE_ALLOCA_H is defined in one of the headers included from nest/bird.h */
+
 #ifdef HAVE_ALLOCA_H
 #include <alloca.h>
 #else
--- lib/resource.h
+++ lib/resource.h
@@ -93,6 +93,7 @@
 #define xrealloc(size) _xrealloc_leap(__FILE__, __LINE__, size)
 #define xfree(ptr) _xfree_leap(__FILE__, __LINE__, ptr)
 #else
+#include <stdlib.h> /* free */
 /*
  * Unfortunately, several libraries we might want to link to define
  * their own xmalloc and we don't want to interfere with them, hence