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