This PR closes out #28716 and #28735 by making two changes to the compiler: 1. The `--emit` flag to the compiler now supports the ability to specify the output file name of a partuclar emit type. For example `--emit dep-info=bar.d,asm=foo.s,link` is now accepted. 2. The dep-info emission now emits a dummy target for all input file names to protect against deleted files.
See the README.md in ../librustc.