Fix GCC 6.4.0 compilation errors #7806

Job	Run time
build (windows-2019, Win32, v142, 17, Debug)	1m 12s
build (windows-2019, Win32, v142, 17, Release)	2m 13s
build (windows-2019, Win32, v142, 17, -DBUILD_SHARED_LIBS=ON, Debug)	2m 8s
build (windows-2019, Win32, v142, 17, -DBUILD_SHARED_LIBS=ON, Release)	2m 8s
build (windows-2019, x64, v141, 14, Debug)	1m 45s
build (windows-2019, x64, v141, 14, Release)	2m 3s
build (windows-2019, x64, v141, 17, Debug)	1m 32s
mingw (mingw64)	3m 38s
mingw (ucrt64)	4m 16s
build (windows-2019, x64, v141, 17, Release)	2m 52s
build (windows-2019, x64, v142, 17, Debug)	1m 24s
build (windows-2019, x64, v142, 17, Release)	2m 30s
build (windows-2019, x64, v142, 17, -DBUILD_SHARED_LIBS=ON, Debug)	1m 21s
build (windows-2019, x64, v142, 17, -DBUILD_SHARED_LIBS=ON, Release)	2m 17s
build (windows-2019, x64, v142, 20, Debug)	1m 44s
build (windows-2019, x64, v142, 20, Release)	2m 55s
build (windows-2022, x64, v143, Debug, 20)	1m 45s
	37m 43s

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