Fetch file -- use axel or prozilla instead of curl

[CHENG Gao]

*On Wed, 31 Jan 2007 11:37:48 -0500
* Kevin Ballard <eridius at macports.org> climbed out of the dark hell and cried out:

> I find it highly unlikely that any speed problems are curl's fault. It's
> hard to write a slow HTTP downloader ;)
>
> Perhaps you should try editing /opt/local/share/darwinports/resources/
> port1.0/fetch/mirror_sites.tcl and reordering the mirror list?

Thanks for the info. I'll try to reorder that.

But anyway tools like axel/prozilla/aget should be faster than curl. Why
not allow them as options? Maybe some setting in conf file, like 

fetchprogram axel or aget or prozilla?

I dont know nothing about Tcl so I have no idea how to hack it. I found
a page describing how to use wget instead, but seems portfetch.tcl has
evolved, and simply change "eval curl" to "system wget/axel ..." wont
work anymore.

Anyway I can accept the situation. The worst solution for me is to  use
axel to get tarballs and put them in corresponding dirs under distfiles.