feat(os): add UserConfigDir and UserCacheDir

[mikesmitty]

Fixes #5040

[deadprogram]

@mikesmitty looks like this needs to be behind a build tag since those functions do not exist in older Go versions.

[aykevl]

internal/filepathlite was added in Go 1.23, so we can't rely on it.

We could, however, have our own internal/filepathlite package instead. For that you'd need to modify the following code to add the package as well:

tinygo/loader/goroot.go

Line 245 in 3869f76

"internal/cm/": false,

(Add "internal/filepathlite": false,, and preferably also a note to the files like "This is needed for Go 1.22 compatibility").

[dgryski]

We'd have to import the entire internal/filepathlite then since the upstream path/filepath (which we use unmodified) was rewritten to use it for most functions.

[b0ch3nski]

... or after 1.26 release we could drop 1.22 support 😸