enh(Poco::Dynamic): Modernised code to use C++17 features. #2784

Job	Run time
android-arm64-v8a-ndk-latest-cmake	8m 32s
android-arm64-v8a-ndk-cmake	8m 24s
android-armeabi-v7a-ndk-cmake	8m 52s
linux-emscripten-cmake	5m 37s
linux-gcc-cmake	16m 58s
linux-gcc-cmake-unbundled	17m 9s
linux-gcc-make	22m 35s
linux-gcc-make-armv7l	14m 19s
linux-gcc-make-asan	27m 2s
linux-gcc-make-asan-no-soo	27m 2s
linux-gcc-make-cross-armhf	14m 10s
linux-gcc-make-cxx20	27m 52s
linux-gcc-make-trace	21m 53s
linux-gcc-make-tsan	22m 4s
linux-gcc-make-ubsan	32m 49s
macos-clang-cmake-openssl3	21m 8s
macos-clang-make	34m 13s
macos-clang-make-visibility-hidden	1s
linux-gcc-make-mongodb	8m 44s
linux-gcc-make-mysql	8m 22s
linux-gcc-make-odbc	13m 11s
linux-gcc-make-postgres	8m 20s
linux-gcc-make-redis	8m 24s
macos-clang-cmake-openssl3-visibility-hidden	19m 57s
linux-gcc-make-sqlite-no-sqlparser	8m 18s
macos-clang-make-openssl3-asan	20m 20s
macos-clang-make-openssl3-tsan	19m 31s
macos-clang-make-openssl3-ubsan	13m 20s
windows-2022-msvc-buildwin-x64	18m 10s
windows-2022-msvc-cmake	17m 20s
windows-2022-msvc-cmake-static	17m 4s
windows-2022-msvc-cmake-static-mt	17m 0s
	8h 48m 41s

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