Add RHEL gating test

Actually the test fails with:

gcc: fatal error: environment variable ‘RPM_ARCH’ not defined

I believe this is caused by the package notes implementation being
broken.  We'll need to fix that separately.

gating.yaml

@@ -0,0 +1,6 @@
+--- !Policy
+product_versions:
+  - rhel-*
+decision_context: osci_compose_gate
+rules:
+  - !PassingTestCaseRule {test_case_name: osci.brew-build.tier0.functional}

tests/basic-test.sh

@@ -0,0 +1,9 @@
+#!/bin/bash -
+set -e
+set -x
+
+# Compile trivial tk program.
+echo 'ignore (Tk.opentk ())' > tktest.ml
+ocamlfind ocamlopt -package labltk tktest.ml -linkpkg -o tktest
+# Unfortunately we can't run this as we won't have an X server available.
+#./tktest

tests/tests.yml

@@ -0,0 +1,13 @@
+- hosts: localhost
+  roles:
+  - role: standard-test-basic
+    tags:
+    - classic
+    required_packages:
+    - ocaml
+    - ocaml-findlib
+    - ocaml-labltk-devel
+    tests:
+    - simple:
+        dir: .
+        run: ./basic-test.sh