It's possible that you could even use this to enumerate all the files in some directory, such that you wouldn't require source code changes in order to add a new post - you'd simply need to run the preprocessor again in a different build environment.
Also, in the spirit of the post: it should be relatively easy to implement this oneself with a build script in Rust. In Go I don't think it's as easy, and iirc the author of the package uses the semi-public 'build tags' API[2] (which always gave me a sense of being grudgingly released, in one of the countless "we core developers mustn't allow the unwashed hordes of lowly application developers to have these dangerous, powerful tools" fights that seem to characterise Go development).
[0] https://github.com/glassbearInc/rs-bindata