interact very nicely with HTTP proxies: Since proxies do not know
that all the files on portsnap1.freebsd.org are identical to the
files with the same names on portsnap2.freebsd.org, said proxies end
up downloading and storing files in duplicate.
This commit uses the HTTP_PROXY environment variable, if set, to
generate a random number seed for use in selecting a mirror. This
means that if several systems all have the same HTTP_PROXY value set,
they will ask the proxy to fetch files from the same mirror (unless
that mirror fails, in which case all the systems will use the same
second choice, et cetera).
Portsnap still doesn't interact very well with "transparent" HTTP
proxies, but there's nothing I can do about those.
Requested by: simon
Sponsored by: FreeBSD security development fundraiser
6a63b482f7