The `fs.relative()` method assumed that the file-system is a single tree, which is not the case in Windows, where you can have multiple drives, e.g. `C:`, `D:` etc. This commit changes `fs.relative()` so that it no longer forces the result to be a `PathSegment` and then flows that refactoring through the rest of the compiler-cli (and ngcc). The main difference is that now, in some cases, we needed to check whether the result is "rooted", i.e an `AbsoluteFsPath`, rather than a `PathSegment`, before using it. Fixes #36777 PR Close #37959
Angular Compatibility Compiler (ngcc)
This compiler will convert node_modules compiled with ngc, into node_modules which
appear to have been compiled with ngtsc.
This conversion will allow such "legacy" packages to be used by the Ivy rendering engine.
Building
The project is built using Bazel:
yarn bazel build //packages/compiler-cli/ngcc
Unit Testing
The unit tests are built and run using Bazel:
yarn bazel test //packages/compiler-cli/ngcc/test
Integration Testing
There are tests that check the behavior of the overall executable:
yarn bazel test //packages/compiler-cli/ngcc/test:integration