diff --git a/src/flipbinpdb.c b/src/flipbinpdb.c
index 94b71ba..01a2529 100644
--- a/src/flipbinpdb.c
+++ b/src/flipbinpdb.c
@@ -9,6 +9,7 @@
 #include <sys/mman.h>
 #include <fcntl.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #ifndef MAP_FILE
 #define MAP_FILE 0
diff --git a/src/flipdcd.c b/src/flipdcd.c
index 8ec85b7..1c23433 100644
--- a/src/flipdcd.c
+++ b/src/flipdcd.c
@@ -13,6 +13,7 @@
 #include <sys/mman.h>
 #include <fcntl.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #ifndef MAP_FILE
 #define MAP_FILE 0