Fix macOS build environment script

[dszakallas]

Update conditional checks in the build environment script to use double brackets.

Single brackets errors with

./tools/macos_buildenv.sh:32: = not found

I am using

bash --version
GNU bash, version 5.3.0(1)-release (aarch64-apple-darwin24.5.0)
Copyright (C) 2025 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

[Copilot]

Pull Request Overview

Fix shell script compatibility issues by updating conditional syntax from single to double brackets to resolve bash parsing errors on macOS.

• Replace single bracket [ with double bracket [[ in conditional statements
• Ensure script compatibility with GNU bash version 5.3.0

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

[nitpick] For consistency with the updated conditional checks, consider updating these remaining single bracket conditionals to use double brackets [[ ]] syntax as well.

[Copilot]

[nitpick] For consistency with the updated conditional checks, consider updating this remaining single bracket conditional to use double brackets [[ ]] syntax as well.

Suggested change

	if [ -n "${BUILDENV_RELEASE}" ]; then
	if [[ -n "${BUILDENV_RELEASE}" ]]; then

[daschuer]

Thank you. The fix looks good. Can you rebase it to the 2.5 branch and change the merge target to 2.5 via the edit button above?

[dszakallas]

Rebasing results in conflicts. Do we need a separate PR in this case?

[JoergAtGithub]

The code differs between 2.5 and 2.6. I recommend to rebase this to 2.6