c codes about unicode string Compare

[longsers]

about unicode string Compare

cheat engine can use {$c}{$ccode} to Compare string,but
Dark Byte say:
including string.h requires all the other string functions to be present as well.


If you want to use #include <string.h>
All required system dlls must be loaded like
loadlibrary(ucrtbase.dll)

How does c language do uncode comparison without #include <string.h>