diff --git a/Build.sh b/Build.sh
index 578c175..07c48c3 100644
--- a/Build.sh
+++ b/Build.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
-# $MirOS: src/bin/mksh/Build.sh,v 1.259 2007/09/09 18:31:41 tg Exp $
+# $MirOS: src/bin/mksh/Build.sh,v 1.260 2007/09/09 19:24:58 tg Exp $
 #-
 # Environment used: CC CFLAGS CPPFLAGS LDFLAGS LIBS NOWARN NROFF TARGET_OS
 # CPPFLAGS recognised:	MKSH_SMALL MKSH_ASSUME_UTF8 MKSH_NEED_MKNOD MKSH_NOPWNAM
@@ -301,6 +301,10 @@ NetBSD)
 	;;
 OpenBSD)
 	;;
+OSF1)
+	HAVE_SIG_T=0; CPPFLAGS="$CPPFLAGS -Dsig_t=nosig_t"
+	warn=' and is still experimental'
+	;;
 Plan9)
 	CPPFLAGS="$CPPFLAGS -D_POSIX_SOURCE -D_LIMITS_EXTENSION"
 	CPPFLAGS="$CPPFLAGS -D_BSD_EXTENSION -D_SUSV2_SOURCE -D__Plan9__"