Support msvc 2

[rkanavath]

to be merged after https://github.com/OSGeo/grass/pull/350

[wenzeslaus]

I don't know what are the relevant changes here (all these old msvc PRs were done from different places on a branch with previous changes accumulated - that's partially why we were never able to review them and merge them).

I suggest closing this when CMake build works on Windows.

[echoix]

It's the last 6 commits that follow #350, on a computer, on files changed, you can filter by commit and use shift+click to select a range of commits to show the changed files of