diff --git a/src/core/preferences.cpp b/src/core/preferences.cpp
index 42abe8ca3..438b2f5b3 100644
--- a/src/core/preferences.cpp
+++ b/src/core/preferences.cpp
@@ -50,6 +50,7 @@
 #include <winreg.h>
 #endif
 
+#include <cstdlib>
 #include "core/utils/fs.h"
 #include "core/utils/misc.h"
 
diff --git a/src/gui/options_imp.cpp b/src/gui/options_imp.cpp
index 7fd81ef64..f930e4326 100644
--- a/src/gui/options_imp.cpp
+++ b/src/gui/options_imp.cpp
@@ -41,6 +41,7 @@
 
 #include <libtorrent/version.hpp>
 
+#include <cstdlib>
 #include "options_imp.h"
 #include "core/preferences.h"
 #include "core/utils/fs.h"