Automated audits fail for www.gnu.org or www.nongnu.org homepages

[EricFromCanada]

Any formulae with homepages on www.gnu.org or www.nongnu.org (209.51.188.116, a.k.a wildebeest1p.gnu.org) consistently fail homepage checks run on GitHub infrastructure, probably because that specific server has a block in place. For comparison, savannah.gnu.org and savannah.nongnu.org (209.51.188.113) work fine. E.g. in a GitHub codespace:

• ⛔️ curl --disable --cookie /dev/null --globoff --show-error --header Accept-Language:\ en --connect-timeout 15 --max-time 25 --retry 1 --retry-max-time 25 --dump-header - --output /dev/null --location https://www.nongnu.org/avrdude/
• ⛔️ curl --disable --cookie /dev/null --globoff --show-error --header Accept-Language:\ en --connect-timeout 15 --max-time 25 --retry 1 --retry-max-time 25 --dump-header - --output /dev/null --location https://www.gnu.org/software/binutils/
• ✅ curl --disable --cookie /dev/null --globoff --show-error --header Accept-Language:\ en --connect-timeout 15 --max-time 25 --retry 1 --retry-max-time 25 --dump-header - --output /dev/null --location https://savannah.gnu.org/

I've posted an issue asking them to remove the block, but if that goes nowhere, we should consider ignoring those checks in .github/workflows/scheduled.yml or removing them from the ~141 affected formulae.