On Jun 22, 2012, at 11:26 PM, TERRY DONTJE wrote:

4. The behavior of --with[out]-verbs is as was described in a prior mail:
  - if --with-verbs is specified, all 3 verbs-based components must succeed
  - if --without-verbs is specified, all 4 verbs-based components will not build
  - if --with-verbs=DIR is specified, all 3 verbs-based components must succeed and will use DIR to find verbs headers and libraries

What does it mean that "all 3 verbs-based components must succeed"?  
Does that mean you cannot specify --with-verbs=DIR --with-openib --without-ofud?

Yes.  --with/without-ofud never worked, anyway (i.e., there was no code that implemented it).  Ditto that there was no --with/without-ud.

Does it mean that if you specify --with-verbs=DIR  and some other dependency is not found for openib btl that the configure fails?

Yes.  Same was true for --with-openib=DIR.

What is the 4th verbs-based component this is not built when one specifies --without-verbs.

There isn't one.  

You're probably thinking of hwloc; hwloc can *use* verbs, but it doesn't *require* verbs.  The other 3 (OOB UD, BTL OFUD, BTL openib) all *require* verbs and cannot be built without it.