Inheritance of macports.conf configuration files

[adambyrtek@…]

There are two possible locations of MacPorts configuration file:
$prefix/etc/macports.conf
$home/.macports/macports.conf

Currently user defined file if present *substitutes* the global file completely. The attached patch allows user to override only a few configuration options, keeping the global file as a default for other options. This is more in line with other Unix tools and more convenient, as often user only wants to tweak a few options keeping the rest in place.

[adambyrtek@…]

Spaces instead of tabs in ChangeLog

[adambyrtek@…]

Quite trivial yet very useful change. Discussed recently on macports-users and more than a year ago at macports-dev:
 http://lists.macosforge.org/pipermail/macports-dev/2007-April/001373.html

[raimue@…]

Committed in r40712.