add FindPatch.cmake

[ghost]

I've added FindPatch.cmake. This is only used when compiling under MSVC. CMake will exit with an error if patch.exe is not found (it'll search in system paths and the default installation directories of msysGit). I've also removed tortoiseGit as it's unneeded (msysGit provides both Git and patch.exe).

This pull needs to be tested on Linux/mingw as I made some changes that could affect these platforms.

[karolherbst]

I like most part of this request, but I am worried about using patch only from a git installation. It should be possible to build desurium on Windows without any git installation (because sometimes you will only download a versioned archive)

[ghost]

CMake will check %PATH% before checking in the git installation. The user is not affected by this change if they already have patch.exe in their path.

[karolherbst]

I think we should also check for patch on Linux, because of #243

[ghost]

It seems extremely unlikely that a developer would have all the necessary dependencies installed to compile Desurium except for patch.

[karolherbst]

it is still a direct dependency and we should check all of them.

FindPatch.cmake should work for UNIX based system as well, shouldn't it? We don't need to configure patch.sh as well, but we should fail if it isn't in PATH

[ghost]

Ok, change has been made.

[karolherbst]

seems fine to me now, thanks

[karolherbst]

last comment and then everything should be fine

[ghost]

Didn't even realise CMAKE_GEN_SRC_DIR existed. It should be all good now.

[karolherbst]

thanks