diff --git a/BasiliskII/src/Unix/prefs_editor_gtk.cpp b/BasiliskII/src/Unix/prefs_editor_gtk.cpp
index a7a03db5..53d45f61 100644
--- a/BasiliskII/src/Unix/prefs_editor_gtk.cpp
+++ b/BasiliskII/src/Unix/prefs_editor_gtk.cpp
@@ -29,6 +29,8 @@
 #include <net/if.h>
 #include <net/if_arp.h>
 
+#include <cerrno>
+
 #ifdef HAVE_GNOMEUI
 #include <gnome.h>
 #endif
diff --git a/SheepShaver/src/Unix/prefs_editor_gtk.cpp b/SheepShaver/src/Unix/prefs_editor_gtk.cpp
index a15337d3..03821908 100644
--- a/SheepShaver/src/Unix/prefs_editor_gtk.cpp
+++ b/SheepShaver/src/Unix/prefs_editor_gtk.cpp
@@ -29,6 +29,8 @@
 #include <net/if.h>
 #include <net/if_arp.h>
 
+#include <cerrno>
+
 #include "user_strings.h"
 #include "version.h"
 #include "cdrom.h"