cmake: Fix 64bit host CPU detection #300

Job	Run time
build-macos (macos-latest)	45s
build-macos (flyci-macos-large-latest-m2)	9s
Build on ubuntu-20.04 g++-7	1m 5s
Build on ubuntu-20.04 g++-8	46s
Build on ubuntu-latest g++-9	58s
Build on ubuntu20.04 aarch64 g++-8	6m 58s
Build on ubuntu-latest g++-10	1m 0s
Build on ubuntu20.04 aarch64 g++-9	7m 25s
Build on ubuntu-20.04 clang-7	54s
Build on ubuntu20.04 aarch64 g++-10	6m 52s
Build on ubuntu-20.04 clang-8	1m 13s
Build static on ubuntu-latest	1m 1s
Build on ubuntu22.04 aarch64 g++-12	7m 10s
Build on ubuntu-20.04 clang-9	54s
Build on ubuntu20.04 aarch64 clang-9	11m 5s
Build on ubuntu-20.04 clang-10	54s
build-windows	2m 17s
Build on ubuntu20.04 aarch64 clang-10	11m 18s
Build on ubuntu-20.04 clang-11	50s
Build on ubuntu22.04 aarch64 clang-14	11m 15s
Build on ubuntu-latest clang-12	1m 0s
Build on ubuntu-latest clang-13	1m 6s
Build on ubuntu22.04 armv7 g++	7m 2s
Build on ubuntu-latest clang-14	1m 1s
Build on ubuntu22.04 ppc64le g++-12	7m 13s
Build on ubuntu22.04 s390x g++-12	5m 48s
Build on ubuntu22.04 riscv64 g++-12	6m 4s
	1h 44m 3s

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