Fix Makefile test to use more compatible syntax

The existing way is not compatible with a lot of shells, including most
bash installations, because the echos that generates the configuration
sent to redis-server doesn't expand the escapes. Adding '-e' to the
echo works under bash, but breaks on the Travis CI server.

This is my attempt to find an alternative that works everywhere.
[committer note: it doesn't work under Solaris make, but the Makefile
was already broken under Solaris make.  Solaris users must use gmake.]

Closes #224 and Closes #221
Fix build under Solaris

Solaris doesn't define the TCP options we try to set.  Let's
ignore those under Solaris.

Closes #207