Add an option to resolve IP address over IPv4 only

[vincentbernat]

Hey!

When providing my own RESOLVE_URL, there is no way to tell the resolution should be done over IPv4 only. Notably, I was not able to specify WGET_CMD as /usr/bin/wget -4. Either we could add a WGET_OPTIONS for arbitrary wget options or add a specific option to force IPv4 for resolution.

Thanks.

[Seb35]

I had this issue too. I ended with a trick:

• create a script /usr/local/lib/extra/wget4 containing /usr/bin/wget -4 $*
• chmod +x /usr/local/lib/extra/wget4
• set WGET_CMD to /usr/local/lib/extra/wget4