lanl/ci: workaround for xlc builds

For some reason the ci builds on ibm nodes (with xl) need help
with finding the pmix libraries installed as part of the build.
Add the library install path to LD_LIBRARY_PATH as a workaround

Signed-off-by: Howard Pritchard <howardp@lanl.gov>

Author: hppritcha

.ci/lanl/gitlab-darwin-ci.yml

@@ -174,6 +174,7 @@ test:ibm:
     - ls
     - module load ibm
     - export PATH=$PWD/install_test/bin:$PATH
+    - export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$PWD/install_test/lib
     - which mpirun
     - pushd examples
     - mpirun -np 4 hostname