[BUG] PREFIX environment variable ignored by git config --system

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Please answer the following questions to help us understand your issue.

What did you do before the bug happened? (Steps to reproduce your issue) export PREFIX=/home/randall git config --system --list

What did you expect to happen? (Expected behavior) Git should use ${PREFIX}/etc/gitconfig instead of the build location to locate System configuration items, per 10.8 in the git-scm website documentation on Environment Variables. Git should have reported: fatal: unable to read config file '/home/randall/etc/gitconfig': No such file or directory

What happened instead? (Actual behavior) git used /usr/local-ssl3.0/etc/gitconfig instead and reported that the file does not exist: fatal: unable to read config file '/usr/local-ssl3.0/etc/gitconfig': No such file or directory

What's different between what you expected and what actually happened? The directory being used based on the PREFIX variable.

Anything else you want to add: This appears to be a problem on all platforms.

[System Info] git version: git version 2.47.1 cpu: NSV built from commit: 92999a42db1c5f43f330e4f2bca4026b5b81576f sizeof-long: 4

[System Info] git version: git version 2.45.1 cpu: x86_64 no commit associated with this build sizeof-long: 8

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