--- /dev/null
+diff --git a/utils/wvuid.cc b/utils/wvuid.cc
+index 7fa1035..709a484 100644
+--- a/utils/wvuid.cc
++++ b/utils/wvuid.cc
+@@ -33,6 +33,7 @@ wvuid_t wvgetuid()
+
+ #else // not WIN32
+
++#include <unistd.h>
+
+ WvString wv_username_from_uid(wvuid_t uid)
+ {