Add debugging to finding clang #20

Job	Run time
i686-pc-windows-msvc/msvc (Debug)	17m 43s
i686-pc-windows-msvc/msvc (Release)	21m 23s
x86_64-pc-windows-msvc/msvc (Debug)	19m 8s
x86_64-pc-windows-msvc/msvc (Release)	22m 5s
aarch64-pc-windows-msvc/msvc (Debug)	5m 2s
aarch64-pc-windows-msvc/msvc (Release)	5m 58s
x86_64-apple-darwin/clang (Debug)	23m 4s
x86_64-apple-darwin/clang (Release)	22m 35s
aarch64-apple-darwin/clang (Debug)	9m 17s
aarch64-apple-darwin/clang (Release)	14m 0s
x86_64-unknown-linux-gnu/gcc (Debug)	8m 52s
x86_64-unknown-linux-gnu/gcc (Release)	17m 22s
x86_64-unknown-linux-gnu/clang (Debug)	8m 47s
x86_64-unknown-linux-gnu/clang (Release)	14m 10s
aarch64-unknown-linux-gnu/gcc (Debug)	1h 0m 20s
aarch64-unknown-linux-gnu/gcc (Release)	48m 8s
aarch64-unknown-linux-gnu/clang (Debug)	1h 0m 13s
aarch64-unknown-linux-gnu/clang (Release)	31m 36s
	6h 49m 43s

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