fix: allow disabling IPv6

[tnyeanderson]

Description

Allows the user to set the IPV6_DISABLE environment variable to a non-empty value to disable lighttpd listening on IPv6.

Fixes: #648

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• I've read & comply with the contributing guidelines
• I have tested my code for new features & regressions on both mobile & desktop devices, using the latest version of major browsers.
• I have made corresponding changes to the documentation (README.md).
• I've checked my modifications for any breaking changes, especially in the config.yml file

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[tnyeanderson]

Hey @bastienwirtz , anything I need to do to get this moving? :)

[bastienwirtz]

Hello @tnyeanderson

Thanks for your contribution, and sorry for the delay !
A few detail but it looks good.

[tnyeanderson]

Should be good to go. Thanks @bastienwirtz !

[tnyeanderson]

Good catch! lol

[bastienwirtz]

Thx @tnyeanderson, I'll test that asap and it should be good to go

[bastienwirtz]

Works fine @tnyeanderson, thanks again !

[gstrauss]

FYI: lighttpd 1.4.72 will issue a warning if IPv6 is not available and will continue without listening on that socket.