ADD: stable env

env/sles15/x86_64/stable/spack.yaml

@@ -0,0 +1,13 @@
+spack:
+  concretizer:
+    unify: false
+  config:
+    allow_sgid: false
+    install_tree:
+      root: $spack/opt/spack/$env
+    build_stage:
+      - /scratch/$user/spack-stage/$env
+    specs:
+      - opal@master%gcc@12.3.0
+  view: false
+