Rollup merge of #66569 - pietroalbini:gha-1, r=alexcrichton

GitHub Actions: preparations, part 1

This PR adds the first batch of commits in preparation for GitHub Actions:

* Added GitHub Actions support in `src/ci/shared.sh` and bootstrap.
* Addded a `setup-environment.sh` script which guesses and sets the `DEPLOY`, `DEPLOY_ALT` and `IMAGE` environment variables automatically, to reduce the verbosity of the CI configuration.

This PR does **not** yet add any builders on GitHub Actions.

r? @alexcrichton

1 files changed, 4 insertions, 0 deletions

diff --git a/src/bootstrap/util.rs b/src/bootstrap/util.rs
index 98ae7b692bb..6f8a6308745 100644
--- a/src/bootstrap/util.rs
+++ b/src/bootstrap/util.rs
@@ -262,6 +262,8 @@ pub enum CiEnv {
     None,
     /// The Azure Pipelines environment, for Linux (including Docker), Windows, and macOS builds.
     AzurePipelines,
+    /// The GitHub Actions environment, for Linux (including Docker), Windows and macOS builds.
+    GitHubActions,
 }
 
 impl CiEnv {
@@ -269,6 +271,8 @@ impl CiEnv {
     pub fn current() -> CiEnv {
         if env::var("TF_BUILD").ok().map_or(false, |e| &*e == "True") {
             CiEnv::AzurePipelines
+        } else if env::var("GITHUB_ACTIONS").ok().map_or(false, |e| &*e == "true") {
+            CiEnv::GitHubActions
         } else {
             CiEnv::None
         }