shims: enable cc arg refurbishment for ninja

[Bo98]

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We do it for Make so we should start doing it for Ninja too now.

[BrewTestBot]

Review period will end on 2022-03-15 at 00:00:00 UTC.

[BrewTestBot]

Review period skipped due to critical label.

[carlocab]

Fine with this. However, I wonder whether the fact that we've gone for so long without refurbishing cc args with ninja with very little problems suggests that we should consider doing less arg refurbishment rather than more of it.

[Bo98]

Well it is causing issues not stripping -march - it's just not widely noticeable because our CI does not test for issues caused by that. Maybe some things are adding debug symbols but the consequences of that are negligible.

The rest are mostly portability and compatibility reasons and as such really shouldn't matter for modern software with a modern build system:

• Being less strict on warnings (good for newer Xcodes that may introduce additional warnings).
• Removing non-Clang flags (most modern build systems usually abstract this away).
• Enforcing mmacosx-version-min to be 10.9 or later (fixes stdlib issues) on 10.13 and later.
• Enforces -isysroot to be Homebrew's choice of SDK (this can be very important for things like curl headers - using a newer SDK can lead to and has led to runtime crahes).
• Preventing -I, -L to non-Homebrew locations (does not impact our CI really, but can be important for users building from source).

For software with a good build system, most of the above should not be a concern. Software using Ninja tend to have more modern build systems.

Ninja is still to be honest quite a small portion of our formulae - it's largely inflated by GNOME formulae. Qt and v8 are two to look out for.

[Bo98]

we should consider doing less arg refurbishment rather than more of it.

To be clear though: I do generally agree with this.

[MikeMcQuaid]

👍🏻 on this, thanks @Bo98!