[build] Fix unset proxy

[hughperkins]

Issue: #

Brief Summary

Fix m1 build failing at end of export symbols

copilot:summary

Walkthrough

See eg https://github.com/hughperkins/taichi/actions/runs/14693755030/job/41232608209

+ git config --global --unset https.proxy
Error: Process completed with exit code 5.

Hypothesis: the git config --unset is causing exit code 5

Test hypothesis locally:

~/git/taichi-m1 (hp/fix-cannot-name-an-alias-template-for-trigger|…1) $ git config --global --unset https.proxy
~/git/taichi-m1 (hp/fix-cannot-name-an-alias-template-for-trigger|…1) $ echo $?
5

Make test function and test locally:

#!/bin/bash

function foobar {
	echo foobar
	exit 5
}

trap foobar EXIT

Test:

~/git/taichi-m1 (hp/fix-cannot-name-an-alias-template-for-trigger|…1) $ bash /tmp/test.sh ; echo $?
foobar
5

=> can control the exit code of the function using an exit

copilot:walkthrough