x/lib: Add LookPath{,All} to envvar, and use it in cmdline.

This exports the LookPath and LookPathAll functionality that used
to live unexported in cmdline.  The API and semantics have been
cleaned up slightly, to make it suitable for external use, and
some tests have been added.

Change-Id: I57bdef40f62095edcff11890197bbbdacdce6cbb
7 files changed
tree: 6ed5e1c49865d71eb6bbb1d00f667d9745feed92
  1. cmd/
  2. cmdline/
  3. dbutil/
  4. envvar/
  5. gosh/
  6. host/
  7. ibe/
  8. metadata/
  9. netconfig/
  10. netstate/
  11. set/
  12. textutil/
  13. timing/
  14. toposort/
  15. vlog/
  16. .gitignore
  17. .godepcop
  18. AUTHORS
  19. CONTRIBUTING.md
  20. CONTRIBUTORS
  21. LICENSE
  22. PATENTS
  23. README.md
  24. VERSION
README.md

This repository contains general purpose libraries used by the Vanadium project. TEST