diff --git a/lang/tcl/8.5/Makefile b/lang/tcl/8.5/Makefile
index 3d0d7b2fd3f..807614a942f 100644
--- a/lang/tcl/8.5/Makefile
+++ b/lang/tcl/8.5/Makefile
@@ -1,4 +1,4 @@
-# $OpenBSD: Makefile,v 1.8 2009/11/21 02:50:23 sthen Exp $
+# $OpenBSD: Makefile,v 1.9 2010/02/06 10:27:21 pirofti Exp $
 
 COMMENT =		Tool Command Language
 
@@ -43,6 +43,10 @@ CONFIGURE_ARGS +=	${CONFIGURE_SHARED} \
 
 CONFIGURE_ENV +=	SHLIB_VERSION="${LIBtcl85_VERSION}"
 
+.if ${MACHINE_ARCH} == "sh"
+CFLAGS +=		-O0
+.endif
+
 FLAVORS =		threaded
 FLAVOR ?=