There is a new pull request by tornaria against master on the void-packages repository

https://github.com/tornaria/void-packages http_proxy
https://github.com/void-linux/void-packages/pull/41435

xbps-src: keep http_proxy and other lowercase proxy variables
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#### Testing the changes
- I tested the changes in this PR: **briefly**

From `curl` manpage:
```
ENVIRONMENT
       The environment variables can be specified in lower case or upper case.
       The lower case version has precedence. http_proxy is an exception as it
       is only available in lower case.
```

I have `http_proxy` and `https_proxy` set, and then `xbps-src update-check` would not use the proxy. With this commit, it works as expected.

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A patch file from https://github.com/void-linux/void-packages/pull/41435.patch is attached