Merge pull request #157 from boostorg/develop #396

Job	Run time
B2 msvc-14.2	9m 38s
B2 gcc-11	4m 32s
CMake msvc-14.2 Debug C++17	10m 5s
B2 msvc-14.3	8m 12s
B2 clang-14	5m 7s
CMake msvc-14.2 Release C++17	9m 6s
CMake msvc-14.3 Debug C++20	9m 58s
CMake msvc-14.3 Release C++20	8m 37s
CMake gcc-11 17 Debug	11m 45s
CMake gcc-11 20 Release	10m 24s
CMake clang-11 17 Debug	5m 49s
CMake clang-11 20 Debug	6m 56s
CMake clang-13 17 Release	7m 22s
CMake clang-13 20 Release	10m 6s
CMake clang-14 17 Debug -stdlib=libc++	10m 15s
CMake clang-14 20 Release -stdlib=libc++	11m 34s
	2h 19m 26s

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