gitlab: add pmix to testsuite

Problem: We need flux-pmix to test OpenMPI v5.0+.

Add it to our tests and check its testsuite against
LC's versions of OpenMPI.

.gitlab-ci.yml

@@ -38,6 +38,25 @@ default:
         - cd $CORE_BUILD_DIR
         - make -j check
 
+.test-pmix:
+    extends: .lc-variables
+    variables:
+        PYTHON: "/usr/bin/python3"
+        debug: t
+        FLUX_TESTS_LOGFILE: t
+    script:
+        - !reference ['.build-core', 'script']
+        - cd $CORE_BUILD_DIR
+        - export PKG_CONFIG_PATH=$(pwd)/lib/pkgconfig:$(pkg-config --variable pc_path pkg-config)
+        - module load openmpi
+        - export PKG_CONFIG_PATH=$(dirname $(which mpicc))/../lib/pkgconfig:$PKG_CONFIG_PATH 
+        - cd ../..
+        - git clone https://github.com/flux-framework/flux-pmix
+        - cd flux-pmix
+        - ./autogen.sh
+        - PKG_CONFIG_PATH=${PKG_CONFIG_PATH} ./configure
+        - $CORE_BUILD_DIR/src/cmd/flux start make -j check
+
 .test-core-mpi:
     extends: .lc-variables
     variables: 
@@ -73,6 +92,12 @@ quartz-core-test:
         - .quartz
     stage: test
 
+corona-pmix-test:
+    extends:
+        - .test-pmix
+        - .corona
+    stage: test
+
 corona-mpi-test:
     extends:
         - .test-core-mpi