Auto merge of #16389 - aneeshusa:support-debian-for-mach-bootstrap, r=jdm
Auto merge of #16389 - aneeshusa:support-debian-for-mach-bootstrap, r=jdm

Allow bootstrapping on Debian

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This is needed for servo/saltfs#631, since the Travis builders are detected as `'debian'` for some reason.

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- [ ] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [ ] There are tests for these changes OR
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