Update `brioche-cc` to find `cc` path under `libexec/brioche-cc` #74

Job	Run time
Run checks	46s
Build artifacts (x86_64-linux, ubuntu-22.04, x86_64-unknown-linux-gnu, x86_64-unknown-linux-musl,...	1m 53s
Run tests (ubuntu-22.04)	50s
Build artifacts (aarch64-linux, ubuntu-22.04, aarch64-unknown-linux-gnu, aarch64-unknown-linux-mu...	2m 15s
Run tests (macos-14)	52s
Build artifacts (x86_64-macos, macos-14, x86_64-apple-darwin, x86_64-apple-darwin, brioche-packed...	1m 45s
Build artifacts (aarch64-macos, macos-14, aarch64-apple-darwin, aarch64-apple-darwin, brioche-pac...	1m 37s
Push artifacts	30s
	10m 28s

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