ACL2(r) books now build correctly.  The problem was in the definv macro, which is too brittle.  I thought at first that tau may be the problem, but I'm no longer sure of that.  It could have been another change, e.g., to the arithmetic libraries.

Still to do: Add the "std" books into ACL2(r).

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2296 303c5b2c-9740-0410-b014-fd8f9db7be32
Minor Makefile mod in support of its (continued) use by nonstd/Makefile.

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2297 303c5b2c-9740-0410-b014-fd8f9db7be32
Added a time element to the idiv circuit and gave the theorems inside it legit hyps.

Fixes issue 120

git-svn-id: http://acl2-books.googlecode.com/svn/trunk@2298 303c5b2c-9740-0410-b014-fd8f9db7be32