fix: expose libgtkui::GetFgColor (backport: 3-1-x)

[Cobinja]

Description of Change

Backport libcc portion of electron/electron#15878 to 3-1-x
/cc @inukshuk

Checklist

• PR description included and stakeholders cc'd
• Patch information is added to appropriate .patches.yaml
• script/update runs without error
• PR title follows semantic commit guidelines

Notes

srcipt/updateruns into the (probably) same error as in #690 (comment)
The patch file actually gets applied, but the script tells otherwise

[codebytere]

hey @Cobinja this patch doesn't apply due to mismatched line numbers; you'll need to ensure it applies locally with script/update. We can get this merged once that's fixed up!

[Cobinja]

@codebytere I forced-pushed a new version. It wasn't the line numbers you suspected. I can't tell what it actually was but I suspect a confusion of line-ending types