Update generator scripts 2

[melonedo]

This commit adds macros and makes it work on Windows.

[melonedo]

I generated in both linux and Windows, and I turns out time_t is different on the two platforms(Clong vs Clonglong).
Without more tests, I think the best choice might be using multi-platform configuration then.

cc @Gnimuc

[Gnimuc]

If time_t is the only one that is system-dependent, then using multi-platform is a bit overkill. I guess it's safe to define it as const time_t = Int in the prologue.jl.

[Gnimuc]

You could also take this as an example for manually adding definitions for different platforms: https://github.com/maleadt/LLVM.jl/blob/master/res/missing_defs.jl

[melonedo]

Thanks! I will try it later.

[visr]

Thanks for this! I cherry picked both commits into #121. The time_t workaround is also used there.