Passing options to zig compiler

[daurnimator]

With C, you can pass in constants to the build process via -D on command line. This can be used for configuring the build artifact in different ways.

I can't seem to find the equivalent in zig. e.g. I might expect that zig build-lib -Dmyarg=foo makes something show up in somewhere like builtin.arguments.

[emekoi]

another solution would be to have a file with the configuration defined in it. passing args would be the equivalent on changing values in the configuration file. you could then @import the file and use the values defined in it.

[Hejsil]

Related #226

[daurnimator]

Thanks @Hejsil. Closing as dupe of #226