Make future changes easier to manage so we only have to change 1 line

instead of 2+. Continuation of previous commit.

src/plugins/mpi/pmix/Makefile.am

@@ -14,6 +14,7 @@ pmix_src = mpi_pmix.c pmixp_agent.c pmixp_client.c pmixp_coll.c pmixp_nspaces.c
 pmix_internal_libs = $(top_builddir)/src/slurmd/common/libslurmd_reverse_tree_math.la
 
 pmix_ldflags = $(SO_LDFLAGS) $(PLUGIN_FLAGS) $(HWLOC_LDFLAGS)
+pmix_libadd = $(pmix_internal_libs) $(PMIX_LIBS) $(HWLOC_LIBS)
 
 # pkglib_v#dir is needed in each one of the below because of the way we
 # use pkglib_v#_LTLIBRARIES even though it is the same for each one it still
@@ -24,7 +25,7 @@ if HAVE_PMIX_V1
 pkglib_v1dir=$(pkglibdir)
 pkglib_v1_LTLIBRARIES = mpi_pmix_v1.la
 mpi_pmix_v1_la_SOURCES = $(pmix_src)
-mpi_pmix_v1_la_LIBADD = $(pmix_internal_libs) $(PMIX_LIBS) $(HWLOC_LIBS)
+mpi_pmix_v1_la_LIBADD = $(pmix_libadd)
 mpi_pmix_v1_la_LDFLAGS = $(pmix_ldflags) $(PMIX_V1_LDFLAGS)
 mpi_pmix_v1_la_CPPFLAGS = $(AM_CPPFLAGS) $(PMIX_V1_CPPFLAGS) -DHAVE_PMIX_VER=1
 
@@ -35,7 +36,7 @@ if HAVE_PMIX_V2
 pkglib_v2dir=$(pkglibdir)
 pkglib_v2_LTLIBRARIES = mpi_pmix_v2.la
 mpi_pmix_v2_la_SOURCES = $(pmix_src)
-mpi_pmix_v2_la_LIBADD = $(pmix_internal_libs) $(PMIX_LIBS) $(HWLOC_LIBS)
+mpi_pmix_v2_la_LIBADD = $(pmix_libadd)
 mpi_pmix_v2_la_LDFLAGS = $(pmix_ldflags) $(PMIX_V2_LDFLAGS)
 mpi_pmix_v2_la_CPPFLAGS = $(AM_CPPFLAGS) $(PMIX_V2_CPPFLAGS) -DHAVE_PMIX_VER=2