Add NMake Support

[fcharlie]

Use NMAKE + VisualStudio command line environment to support more versions of VisualStudio

[andralex]

This looks like a maintenance liability going forward. Is it possible to standardize on only one make program for Windows?

[fcharlie]

@andralex Yes, this just was Phobos in Windows using VisualStudio build easy

[dnadlinger]

The path issue you mentioned in #2621 could also be fixed in the existing make files. The issue here is that apparently (as per some previous, related discussions) VS users generally don't know about the special command line prompt. I personally doubt that, as it is even in the start menu and it should be possible to give nice error messages in the make file if the correct env vars are not set, but I digress.

In any case, there is near-zero chance that yet another make file will be added because of the maintenance overhead (the problem is bad enough already). This is not to say that the used make program can't change, though, or that we couldn't offer more convenient ways to set up a build environment (some progress has recently been made on this in the form of Digger).

[yebblies]

What maintenance liability? Just add it and ignore it, let somebody who cares about this particular build process patch it when it breaks. Just like with do with the vs project files and xcode projects. No autotester no official support, but having it there doesn't cost us.

[rainers]

I also recommend reducing the number of makefiles rather than increasing them.

Until some time ago, I used a windows gnu make clone to build druntime and phobos using posix.mak. There were only a few modifications necessary, but the continuous conflicts stopped me from maintaining it any longer.

See also dlang/druntime#960 for some improvements to druntime's win64.mak.

[fcharlie]

@rainers My VisualStudio is Installed on D:\VisualStudio\12, dlang/druntime#960 ，Not Find cl.exe.
@klickverbot @yebblies
Phobos build environment need to be introspective, perhaps, unifying construct, akin to CMake

[WalterBright]

I agree that that having multiple makefiles for the same target would cause more confusion, especially if one of them is not maintained properly.