Add define guards to avoid multi-inclusion;Limit the size of various MAXCHUNK definitions #985

Job	Run time
minimal (windows-2019)	7m 7s
shared (windows-2019, win64, VC-WIN64A enable-fips)	21m 3s
minimal (windows-2022)	7m 14s
shared (windows-2019, win32, VC-WIN32 --strict-warnings no-fips)	23m 54s
shared (windows-2022, win64, VC-WIN64A enable-fips)	21m 24s
shared (windows-2022, win32, VC-WIN32 --strict-warnings no-fips)	25m 5s
plain (windows-2019)	13m 37s
plain (windows-2022)	13m 46s
	2h 13m 10s

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