Update iostreams from develop #2783

Job	Run time
b2-windows (windows-2019)	29m 25s
b2-windows (windows-2022)	29m 46s
cmake-install-posix (ubuntu-20.04)	4m 41s
b2-posix (ubuntu-20.04)	12m 45s
cmake-install-posix (ubuntu-22.04)	4m 35s
b2-posix (ubuntu-22.04)	12m 50s
cmake-install-windows (windows-2019)	8m 59s
cmake-test-posix (ubuntu-latest)	39m 5s
cmake-install-posix (ubuntu-24.04)	6m 8s
b2-posix (ubuntu-24.04)	13m 52s
cmake-install-windows (windows-2022)	8m 31s
cmake-install-posix (macos-13)	7m 31s
b2-posix (macos-13)	34m 39s
cmake-install-posix (macos-14)	4m 49s
cmake-test-posix-quick (ubuntu-20.04)	1m 51s
b2-posix (macos-14)	9m 51s
cmake-test-windows-quick (windows-2019)	5m 51s
cmake-test-posix-quick (ubuntu-22.04)	2m 8s
cmake-install-posix (macos-15)	4m 51s
b2-posix (macos-15)	10m 15s
cmake-test-windows-quick (windows-2022)	5m 24s
cmake-test-posix-quick (ubuntu-24.04)	2m 18s
cmake-test-posix-quick (macos-13)	6m 59s
cmake-test-posix-quick (macos-14)	4m 6s
cmake-test-posix-quick (macos-15)	3m 53s
	4h 35m 3s

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