Path mapping improves disk/remote cache hit ratio by automatically
removing the configuration-specific path segments (e.g.
`k8-fastbuild-ST-12345678`) from action command lines before staging
them for execution.

This commit makes the stdlib, compilepkg (assuming no cgo) and
gentestmain actions compatible with path mapping, which is mostly
automatic except that `GOROOT` now needs to be passed in via a flag
rather than an environment variable.

Can be tested via `--experimental_output_paths=strip` with Bazel
last_green.

See https://www.youtube.com/watch?v=Et1rjb7ixUU for more information on
path mapping.

This sentinel feature allows the C++ toolchain configuration to use distinct
sets of flags when compiling Go rules.

`bazel mod tidy` is run if supported and if relevant files change due to the command.

When configuring nogo() to run the revive linter, we currently see
builds of testmain.go files fail with the following error:

    if block ends with call to os.Exit function, so drop this else and outdent its block (move short variable declaration to its own line if necessary)

Let's restructure this code slightly, so that this is no longer an
issue.

This reverts commit fcd6390.

`purego` regresses performance of certain third-party libraries (see #3959).

This PR helps prepare the patch release to include f81ce9f

…endencies (#3960)

* Update link in rules.md

upd

* nit

see #3967

and enola-dev/enola#713

* Add linux/ppc64le to GOARCH constraints

This also updates `platforms` module dependency to 0.0.10

Signed-off-by: Chaitanya Munukutla <chaitanya.m61292@gmail.com>

* Support older versions of Bazel

Signed-off-by: Chaitanya Munukutla <chaitanya.m61292@gmail.com>

---------

Signed-off-by: Chaitanya Munukutla <chaitanya.m61292@gmail.com>

A query like kind("go_library", ...) also returns rules that are not go 
libraries but have go_library as a substring of the rule name, e.g. 
not_a_go_library. To fix that, add regex anchors.

* WIP: Add a full `fs.FS` implementation to `runfiles`

* Extract out common implementation

* Minimal feature parity for manifest implementation

* Implement manifest except for dir statting plus test

* Test info

* Add basic trie implementation

* Fully fix test

* Simplify

* Vendor testfs

* FIx tests

* Cleanup

* Simplify

* Root symlinks

* Simplify further

* Add comments and refactor

* Adopt test to Bzlmod

* Also materialize canonical names

* Adjust comment

* Attempt to throw test failures

* Attemp to fix WIndows #2

* Fix test #3

* Address review comments

* Fix test

* Address review comments

* Rename links for better test coverage

* Rename manifest dir entries

* Add `String()` implementations and faithfully fake runfiles dir

* Resolve one layer of symlinks in directory impl

* Resolve all symlinks