问个关于postfix安装的问题

北京外来户

1.make时候出现如下错误：
  make -f Makefile.in MAKELEVEL= Makefiles
(echo "# Do not edit -- this file documents how Postfix was built for your machine."; /bin/sh makedefs) >makedefs.tmp
No <db.h> include file found.
Install the appropriate db*-devel package first.
See the RELEASE_NOTES file for more information.
make: *** [Makefiles] 错误 1
make: *** [Makefiles] 错误 2
我已经用apt安装了db*-devel的。

2.如何改变postfix的安装目录，好象在make install时候指定的目录并不好用，运行postfix start的时候程序要到/etc下找配置文件

环境：debian 3.1 sarge，postfix 2.4