[MERGE] Fixes to configure.in and build-test layer-01

While doing some build-testing I've noticed that configure doesn't
handle gracefully some malformed --with(out) arguments.

This patch addresses three related issues:
- makes the error messages for those cases more informative
- changes some (echo + exit) sequences into AC_MSG_ERROR() standard
autoconf macros
- changes the layer-01 test options so that it doesn't invoke invalid
configure options

Note that build-test layer-01, now that it actually builds, fails for me
on Gentoo Linux on x86 with an error

testIPAddress.cc:597:Assertion
Test name: testIPAddress::testAddrInfo
equality assertion failed
- Expected: 2
- Actual : 10

I expect this to be triggered by some ipv6-related option (or
combination of options) set in configure by layer-01.
This patch does NOT address that issue.

Kinkie