diff --git a/lib/setup.h b/lib/setup.h
index 60d305e8f9..ebab1367db 100644
--- a/lib/setup.h
+++ b/lib/setup.h
@@ -100,6 +100,10 @@ typedef unsigned char bool;
 #endif
 #include <errno.h>
 
+#ifdef __TANDEM /* for nsr-tandem-nsk systems */
+#include <floss.h>
+#endif
+
 #ifndef OS
 #ifdef WIN32
 #define OS "win32"
diff --git a/src/setup.h b/src/setup.h
index 8c6970ab29..d11e7300aa 100644
--- a/src/setup.h
+++ b/src/setup.h
@@ -62,6 +62,10 @@
 
 #include <stdio.h>
 
+#ifdef __TANDEM
+#include <floss.h>
+#endif
+
 #ifndef TRUE
 #define TRUE 1
 #endif