diff --git a/BasiliskII/src/slirp/tcp_input.c b/BasiliskII/src/slirp/tcp_input.c
index c0151610..e7f79601 100644
--- a/BasiliskII/src/slirp/tcp_input.c
+++ b/BasiliskII/src/slirp/tcp_input.c
@@ -42,6 +42,7 @@
  * terms and conditions of the copyright.
  */
 
+#include <stdlib.h>
 #include <slirp.h>
 #include "ip_icmp.h"
 
diff --git a/BasiliskII/src/slirp/udp.c b/BasiliskII/src/slirp/udp.c
index 723a49c1..61978424 100644
--- a/BasiliskII/src/slirp/udp.c
+++ b/BasiliskII/src/slirp/udp.c
@@ -42,6 +42,7 @@
  * terms and conditions of the copyright.
  */
 
+#include <stdlib.h>
 #include <slirp.h>
 #include "ip_icmp.h"