Merge the following from the English version:
1.216 -> 1.221 doc/ja_JP.eucJP/books/porters-handbook/book.sgml
Submitted by: Hiroo Ono <hiroo _at_ jp dot FreeBSD dot org>
Reviewed by: Yoshihiro Hosaka <hosaka dot yoshihiro _at_ gmail dot com>
ryusuke
References: [doc-jp-work 1362, 2094, 2102]