berkeley-db: --enable-sql

support for sqlite interface

adds `dbsql` command

suggestion only since i didn't know the threshold for deciding to (1) add an option, (2) if so, make it default or not, or (3) kitchen sink.

with --enable-sql:

    /usr/local/Cellar/berkeley-db/5.3.21: 5274 files, 118M, built in 4.4 minutes

without:

    /usr/local/Cellar/berkeley-db/5.3.21: 5269 files, 110M, built in 3.9 minutes


http://docs.oracle.com/cd/E17076_02/html/api_reference/C/dbsql.html

http://www.oracle.com/technetwork/database/berkeleydb/db-faq-095848.html#WhataretheBenefitsofUsingtheBerkeleyDBSQLInterface