In permissive mode, during audit module handling, check_gcs is unaware
that it is handling audit modules rather than the binary itself. It
causes the loader to fail to load the audit module, rather than
loading it and disabling GCS.
Also extends GCS tests with 4 LD_AUDIT tests:
1. tst-gcs-audit-disabled: checks if the audit module without GCS
marking is loaded with default gcs support.
2. tst-gcs-audit-enforced: checks if the audit module without GCS
marking is not loaded when GCS is enforced.
3. tst-gcs-audit-optional: checks if the audit module without GCS
marking is loaded when GCS is optional.
4. tst-gcs-audit-override: check if the audit modules without GCS
marking is loaded when GCS is overrided.
Checked on aarch64-linux-gnu with Linux 6.18 on Apple M4 emulated (for
BTI support) and on qemu 10.1.50 simulated (for GCS).
Reviewed-by: Yury Khrustalev <yury.khrustalev@arm.com>
Tested-by: Yury Khrustalev <yury.khrustalev@arm.com>
088a2055da