In message <Pine.NEB.4.62.0508241723460.639@pilchuck.reedmedia.net>, "Jeremy C.
 Reed" writes:
>Is there any way to override the MASTER_SITES (such as on a one-time 
>basis) without editing Makefile?
>
>I'd like to set something like:
>OVERRIDE_MASTER_SITES=ftp://ftp.example.foo/..../distfiles/
>
>Or is there any way to make it always use MASTER_SITE_BACKUP?
>
>I have a few sites that are slow or closing a lot and don't want to edit 
>Makefile.
>
>Also, it may be nice to allow having multiple local distfile directories. 
>I am using a system that has three distfile directories that are not 
>shared, but do have some distfiles I could use. Instead of manually making 
>symlinks for files, it may be useful to have some pkgsrc setting for 
>defining a that multiple distfiles directories are available to look in 
>(but only store in one if downloading).

DIST_PATH is probably what you want to use.  In pkgsrc/mk/defaults:
#DIST_PATH=     /cdrom/0/distfiles:${HOME}/distfiles
# colon-delimited list of directories in which to search for
# ${DISTFILES} and ${PATCHFILES}.  If the requested file is not in any
# of the directories in ${DIST_PATH}, it will be downloaded into
# ${DISTDIR}.  If the requested file is in one of the directories in
# ${DIST_PATH}, a symbolic link will be made to it from ${DISTDIR}. 
# ${DIST_PATH} directories will will be searched before ${DISTDIR},
# letting a CD hold the main distfiles archive, and local ${DISTDIR}
# hold any updated distfiles, for example.
# Possible:  any directories
# Default: none

I use this so that machines can use my mirror in AFS, yet download
packages locally if they're not mirrored.

-Tracy