Upstream commit:
Date: Mon Oct 6 10:39:47 2014 +0800
[BUILTIN] Exit without arguments in a trap should use status outside traps
POSIX now requires that exit without arguments in a trap should
return the last command status prior to executing traps. This
patch implements this behaviour.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>