[GEN][ZH] Add endian compat for BIGFileSystems

[Mauller]

This PR is a prerequesit to a PR to unify AsciiString, it adds endian compatibility functions within an endian_compat header.

These are then used in the StdBIGFileSystem as it was previously relying on the ntohl function which was being indirectly provided through the windows header in AsciiString.

This change is necessary to provide cross compat byte swapping functionality.

[Mauller]

Updated with a more fleshed out endian handling compatability header.

[Mauller]

Updated, Rebased off main and merge conflict fixed.

Tweaked with discussed changes and added endian compat functions to win32Bigfilesystems for generals and zero hour along with stdbigfilesystem.

Should be good to go now.

[xezon]

VC6 does not like the variadic macro. Then we need to do #define static_assert(a,b) and we settle on static asserts always requiring 2 arguments for now.

[Mauller]

VC6 does not like the variadic macro. Then we need to do #define static_assert(a,b) and we settle on static asserts always requiring 2 arguments for now.

Yeah i just noticed this, was just about to change it, should be up in a few seconds.

[Mauller]

Now it doesn't like long long, this is taking a long long time. i should really sort my local VC6 build environment lol.

[xezon]

Looks good.

[Mauller]

Looks good.

It would seem that VC6 doesn't like the helper templates

EDIT: Figured it out, VC6 doesn't support #pragma once and i didn't include traditional header guards.

EDIT2: Nvm wasn't that...