Revert "Add le32toh function which is missing on at least Windows."

This reverts commit bebd611dc52b294be4e2c35fa54d3c2743b36a4e.

Because Linux uses macros for these types of functions, we cannot
replace them with a function. New fix will follow.
Add le32toh macro & friends to platform that lack it, like Windows.

Macros are preferable, because Linux internally uses macros, and
attempting to use a function messes with that.