cmake: Fix `-pthread` flags in summary #3956

Job	Run time
ASan + LSan + UBSan + integer, no depends, USDT	43m 26s
macOS 14 native, arm64, no depends, sqlite only, gui	9m 36s
test each commit	0s
macOS 14 native, arm64, fuzz	7m 18s
Win64 native, VS 2022	2h 11m 46s
Win64 native fuzz, VS 2022	45m 23s
	3h 57m 29s

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