implement 'realpath' in Host to properly resolve symlinks

[vladima]

With microsoft/TypeScript#8486 it is now possible to follow symlinks obtained as a result of module resolution to its actual location. In order to support this custom implementations of CompilerHost should expose realpath function which will be called by the compiler as an epilogue of node module resolution.

[octogonz]

For context, the realpath function is a fix for a real bug that my project encountered when using the "npm link" command. For a repro, try running build.cmd from this archive:

NpmLinkRepro2.tar.gz

[kruncher]

I am experiencing the symlink issue whilst using TypeScript with gulp-typescript.

I tried following the following advise from the readme of this project:

npm install typescript@next
...
Or in combination with a tsconfig file:

var tsProject = ts.createProject('tsconfig.json', {
    typescript: require('typescript')
});

However the issue still persists and I am not entirely sure whether gulp-typescript is using the latest development build or the older one that still exhibits this issue.

Many thanks

[ivogabe]

@kruncher symlinks were not supported yet when you wrote that, that was what this issue was tracking. You can now try the latest version, which should support them.