scripts: fix catching failures

POSIX 1003.1-2008 does not say whether "set -e" should catch a sub-shell
that exits with !0 (it has a list of conditions to catch, but no list of
conditions not to catch, and this situation is not listed).

bash-3 does not catch such a failure, but bash-4 does. That why, on my
Squeeze system I did not see the issue, while Thomas did on is Lenny chroot.

Reported-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

diff -durN ltrace-0.5.1.orig/Makefile.in ltrace-0.5.1/Makefile.in

--- ltrace-0.5.1.orig/Makefile.in	2009-03-16 17:24:08.000000000 +0100

+++ ltrace-0.5.1/Makefile.in	2009-03-16 17:43:09.000000000 +0100

@@ -5,6 +5,7 @@

 OS		:= @HOST_OS@

 ARCH		:= $(shell echo "@HOST_ARCH@" |sed -e s/i.86/i386/      \

 						   -e s/sun4u/sparc64/  \

+						   -e s/alpha.*/alpha/  \

 						   -e s/arm.*/arm/      \

 						   -e s/sa110/arm/      \

 						   -e s/ppc64/ppc/      \