--- fwbuilder-5.1.0.orig/src/libfwbuilder/src/fwbuilder/ThreadTools.h
+++ fwbuilder-5.1.0/src/libfwbuilder/src/fwbuilder/ThreadTools.h
@@ -31,6 +31,7 @@

 #include <time.h> //for time_t definition
 #include <pthread.h>
+#include <unistd.h>

 #include <string>
 #include <queue>