diff --git a/celestia/src/celestia/kde/kdeapp.cpp b/celestia/src/celestia/kde/kdeapp.cpp
index 5e40770..c16840d 100644
--- a/celestia/src/celestia/kde/kdeapp.cpp
+++ b/celestia/src/celestia/kde/kdeapp.cpp
@@ -16,6 +16,7 @@
  ***************************************************************************/
 
 
+#include <unistd.h>
 #include <libintl.h>
 #include <fstream>
 #include <sstream>