old netbsd make set -e vs check-TESTS

[Kevin Ryde]

On an old m68k-unknown-netbsd1.4.1, /usr/bin/make executes commands
using "/bin/sh -ec <command>".

In the check-TESTS rule from automake 1.8.4, the part

        test -n "$$skipped" && echo "$$skipped"

is false (because I had no skipped tests), making the check stop and
fail at that point.

This behaviour from make is probably contrary to posix (which talks
about running commands the same as "system()"), but I wondered if it's
something automake is meant to cope with.


I looked for a crib note in the portability section of the autoconf
manual, to see if this was an old or not so old matter.  (Might try to
get something added there, I got bitten in one of my own rules too.)