VS2010 x86 doesn't accept `LLU` suffix on numbers

[ip7z]

VS2010 x86 doesn't accept LLU suffix in numbers:
C2059: syntax error : 'bad suffix on number'.
zstd.h file:

#define ZSTD_MAX_INPUT_SIZE ((sizeof(size_t)==8) ? 0xFF00FF00FF00FF00LLU : 0xFF00FF00U)

ULL suffix probably fixes such issues.

[Cyan4973]

Note: there are Visual Studio tests run in CI, and so far, none of them seems to suffer from LLU vs ULL. Btw, both suffixes are supposed to be valid according to C99 and C11 standards.
So I guess this outcome may depend on the exact version number of Visual Studio, and it's unfortunate that we can't test the failing versions with Github Actions, presumably because they are older than support limit. This situation would force us to deploy a "blind" fix, without observing the success (or the drawbacks).