Put in an earlier include of sys/signal.h (within ifdef USE_GUSI) to forestal a multiple define.
diff --git a/Mac/tclmods/tclMacNotify.c b/Mac/tclmods/tclMacNotify.c
index 140dadb..8fc313a 100644
--- a/Mac/tclmods/tclMacNotify.c
+++ b/Mac/tclmods/tclMacNotify.c
@@ -13,6 +13,10 @@
* SCCS: @(#) tclMacNotify.c 1.36 97/05/07 19:09:29
*/
+#ifdef USE_GUSI
+/* Move this include up otherwise tclPort.h tried to redefine signals */
+#include <sys/signal.h>
+#endif
#include "tclInt.h"
#include "tclPort.h"
#include "tclMac.h"
diff --git a/Mac/tclmods/tclSelectNotify.c b/Mac/tclmods/tclSelectNotify.c
index ea35fc6..a728442 100644
--- a/Mac/tclmods/tclSelectNotify.c
+++ b/Mac/tclmods/tclSelectNotify.c
@@ -23,6 +23,10 @@
#pragma import reset
#endif
+#ifdef USE_GUSI
+/* Move this include up otherwise tclPort.h tried to redefine signals */
+#include <sys/signal.h>
+#endif
#include "tclInt.h"
#include "tclPort.h"
#include <signal.h>