ci: clean stale Frontier build slugs before compile, fix famd LD_LIBRARY_PATH ordering

On Frontier, the compute-node build step previously inherited whatever
CMake state the login-node --deps-only step left behind. Wipe compiled
Fortran staging/install slugs before each build while preserving dep
dirs (silo, hdf5, lapack, fftw) that require internet to fetch.

Also remove trailing whitespace in famd LD_LIBRARY_PATH export.

Author: Spencer Bryngelson

.github/workflows/common/build.sh

@@ -25,9 +25,23 @@ fi
 # source code is built here on the compute node.
 # Phoenix: always start fresh to avoid SIGILL from stale binaries compiled
 # on a different microarchitecture.
+# Frontier: wipe only compiled Fortran staging/install slugs; preserve dep
+# dirs (silo, hdf5, lapack, fftw) which were built on the login node and
+# cannot be re-fetched from a compute node (no internet).
 if [ "$job_cluster" = "phoenix" ]; then
     source .github/scripts/clean-build.sh
     clean_build
+elif [ "$job_cluster" = "frontier" ] || [ "$job_cluster" = "frontier_amd" ]; then
+    for _dir in build/staging/ build/install/; do
+        if [ -d "$_dir" ]; then
+            for _sub in "$_dir"*/; do
+                _name=$(basename "$_sub")
+                case "$_name" in silo|hdf5|lapack|fftw) continue ;; esac
+                rm -rf "$_sub"
+            done
+        fi
+    done
+    unset _dir _sub _name
 fi
 
 source .github/scripts/retry-build.sh

toolchain/bootstrap/modules.sh

@@ -145,7 +145,7 @@ if [ "$u_c" '==' 'famd' ]; then
     export CRAY_MPICH_LIB="-L${CRAY_MPICH_PREFIX}/lib \
                         ${CRAY_PMI_POST_LINK_OPTS} \
                         -lmpifort_amd -lmpi_amd -lmpi -lpmi -lpmi2"
-    export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:${CRAY_LD_LIBRARY_PATH}" 
+    export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:${CRAY_LD_LIBRARY_PATH}"
     export CMAKE_PREFIX_PATH="${OLCF_AFAR_ROOT}:${CMAKE_PREFIX_PATH}"
     export FC="${OLCF_AFAR_ROOT}/bin/amdflang"