### Rationale for this change
Continues building out support for Meson as a build system generator
### What changes are included in this PR?
This adds the flight directory to the Meson configuration
### Are these changes tested?
Locally
### Are there any user-facing changes?
No
* GitHub Issue: #46141
Authored-by: Will Ayd <william.ayd@icloud.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>
