attempt to run on external host and gh hosts

.github/workflows/ci_ubuntu.yml

@@ -15,21 +15,35 @@ env:
 
 jobs:
   CI:
+    runs-on: ${{ matrix.config.os }}
     runs-on: [self-hosted, linux, ARM64, aws]
     strategy:
       fail-fast: false
       matrix:
         config:
           - {
-              name: "GCC",
+              os: [self-hosted, linux, ARM64, aws],
+              name: "Ubuntu Graviton GCC",
               cc: "gcc",
               cxx: "g++"
-            }
+            },
       #    - {
       #        name: "Clang",
       #        cc: "clang-12",
       #        cxx: "clang-cpp-12"
       #      }
+          - {
+              os: ubuntu-latest,
+              name: "Ubuntu x86 GCC",
+              cc: "gcc",
+              cxx: "g++"
+            },
+          - {
+              os: ubuntu-latest,
+              name: "Ubuntu x86 Clang",
+              cc: "clang-12",
+              cxx: "clang-cpp-12"
+            }
     name: ${{ matrix.config.name }}
     defaults:
       run: