diff --git a/Build.sh b/Build.sh
index 5bd5bb6..5ea2c8d 100644
--- a/Build.sh
+++ b/Build.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
-srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.509 2012/02/17 09:49:45 tg Exp $'
+srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.510 2012/02/17 13:59:56 tg Exp $'
 #-
 # Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
 #		2011, 2012
@@ -155,7 +155,7 @@ ac_testnnd() {
 	else
 		fr=0
 	fi
-	ac_testinit "$@" || return
+	ac_testinit "$@" || return 1
 	cat >conftest.c
 	vv ']' "$CC $CFLAGS $CPPFLAGS $LDFLAGS $NOWARN conftest.c $LIBS $ccpr"
 	test $tcfn = no && test -f a.out && tcfn=a.out
@@ -174,9 +174,10 @@ ac_testnnd() {
 		test $ct = sunpro && vscan='-e ignored -e turned.off'
 	fi
 	test -n "$vscan" && grep $vscan vv.out >/dev/null 2>&1 && fv=$fr
+	return 0
 }
 ac_testn() {
-	ac_testnnd "$@"
+	ac_testnnd "$@" || return
 	rmf conftest.c conftest.o ${tcfn}* vv.out
 	ac_testdone
 }
@@ -1265,7 +1266,7 @@ else
 		#define EXTERN
 		#define MKSH_INCLUDES_ONLY
 		#include "sh.h"
-		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.509 2012/02/17 09:49:45 tg Exp $");
+		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.510 2012/02/17 13:59:56 tg Exp $");
 		int main(void) { printf("Hello, World!\n"); return (0); }
 EOF
 	case $cm in
@@ -1550,7 +1551,7 @@ eval test 1 = \$HAVE_COMPILE_TIME_ASSERTS_$$ || exit 1
 #
 $e "${bi}run-time checks follow$ao, please ignore any weird errors"
 
-ac_testnnd silent_idivwrapv '' '(run-time) whether signed integer division overflows wrap silently' <<-'EOF'
+if ac_testnnd silent_idivwrapv '' '(run-time) whether signed integer division overflows wrap silently' <<-'EOF'
 	#define MKSH_INCLUDES_ONLY
 	#include "sh.h"
 	#ifdef SIGFPE
@@ -1581,19 +1582,21 @@ ac_testnnd silent_idivwrapv '' '(run-time) whether signed integer division overf
 	}
 	#endif
 EOF
-if test $fv = 0; then
-	echo "| hrm, compiling this failed, but we will just failback"
-else
-	echo "| running test programme; this will fail if cross-compiling"
-	echo "| in which case we will gracefully degrade to the default"
-	./$tcfn >vv.out 2>&1
-	rv=$?
-	echo "| result: `cat vv.out`"
-	fv=0
-	test $rv = 0 && test x"`cat vv.out`" = x"si" && fv=1
+then
+	if test $fv = 0; then
+		echo "| hrm, compiling this failed, but we will just failback"
+	else
+		echo "| running test programme; this will fail if cross-compiling"
+		echo "| in which case we will gracefully degrade to the default"
+		./$tcfn >vv.out 2>&1
+		rv=$?
+		echo "| result: `cat vv.out`"
+		fv=0
+		test $rv = 0 && test x"`cat vv.out`" = x"si" && fv=1
+	fi
+	rmf conftest.c conftest.o ${tcfn}* vv.out
+	ac_testdone
 fi
-rmf conftest.c conftest.o ${tcfn}* vv.out
-ac_testdone
 ac_cppflags
 
 $e "${bi}end of run-time checks$ao"