POSIX conditional compilation:

* All features related to POSIX environments (env vars, shell stuff) gated by feature flags
* Dependencies optional per feature flags
* new CI target for non-POSIX build
* new CI target for release binary artifact

Signed-off-by: Ava Hahn [ava@sunnypup.io](mailto:ava@sunnypup.io)

.gitlab-ci.yml

@@ -1,11 +1,29 @@
 default:
   image: rust:latest
 
-compile:
+compile-with-posix-features:
   stage: build
   script:
     - cargo build
 
+compile-without-posix-features:
+  stage: build
+  script:
+    - cargo build --no-default-features
+
+compile-release:
+  stage: build
+  script:
+    - cargo build --release
+  artifacts:
+    paths:
+      - target/release/relish
+  only:
+    variables:
+      - $CI_COMMIT_TAG =~ /^v\d+.\d+.\d+-?.*$/
+  except:
+    - branches
+
 unit-tests:
   stage: test
   script: