This means a validate build can be installed locally.
`pwd`/inst probably won't give a useful value on all platforms (in
particular there are probably some Windows configurations it doesn't
work for), but I don't think it will ever make the build fail.
-./configure $config_args
+./configure "--prefix=`pwd`/inst" $config_args
make Validating=YES -j$threads
fi # testsuite-only
make Validating=YES -j$threads
fi # testsuite-only