oshmem: disable if no spmls build

This patch disables the oshmem layer if there are no SPMLs that
will build.  With the limited set of SPMLs available to support
oshmem, many builds end up installing an oshmem library that we
know will not work.  There has been a bit of customer confusion
over oshmem, hopefully this will lead customers in the right
direction.

Signed-off-by: Brian Barrett <bbarrett@amazon.com>

NEWS

@@ -59,6 +59,9 @@ Master (not on release branches yet)
 ------------------------------------
 
 - Fix rank-by algorithms to properly rank by object and span
+- Do not build Open SHMEM layer when there are no SPMLs available.
+  Currently, this means the Open SHMEM layer will only build if
+  a MXM or UCX library is found.
 
 3.1.0 -- May, 2018
 ------------------

config/opal_summary.m4

@@ -76,8 +76,10 @@ EOF
 
     if test "$project_oshmem_amc" = "true" ; then
         echo "Build Open SHMEM support: yes"
-    else
+    elif test -z "$project_oshmem_amc" ; then
         echo "Build Open SHMEM support: no"
+    else
+	echo "Build Open SHMEM support: $project_oshmem_amc"
     fi
 
     if test $WANT_DEBUG = 0 ; then

configure.ac

@@ -272,8 +272,8 @@ m4_ifndef([project_ompi], [project_ompi_amc=false])
 AS_IF([test "$enable_orte" != "no"], [project_orte_amc=true], [project_orte_amc=false])
 m4_ifndef([project_orte], [project_orte_amc=false])
 
-AS_IF([test "$enable_oshmem" != "no"], [project_oshmem_amc=true], [project_oshmem_amc=false])
-m4_ifndef([project_oshmem], [project_oshmem_amc=false])
+AS_IF([test "$enable_oshmem" != "no"], [project_oshmem_amc=true], [project_oshmem_amc="no (disabled)"])
+m4_ifndef([project_oshmem], [project_oshmem_amc="no (not available)"])
 
 if test "$enable_binaries" = "no" && test "$enable_dist" = "yes"; then
     AC_MSG_WARN([--disable-binaries is incompatible with --enable dist])
@@ -1106,6 +1106,23 @@ OPAL_MCA
 
 m4_ifdef([project_ompi], [OMPI_REQUIRE_ENDPOINT_TAG_FINI])
 
+# Last minute disable of OpenSHMEM if we didn't find any oshmem SPMLs
+if test "$project_oshmem_amc" = "true" && test $OSHMEM_FOUND_WORKING_SPML -eq 0 ; then
+    # We don't have an spml that will work, so oshmem wouldn't be able
+    # to run an application.  Therefore, don't build the oshmem layer.
+    if test "$enable_oshmem" != "no" && test -n "$enable_oshmem"; then
+	AC_MSG_WARN([No spml found, so OpenSHMEM layer will be non functional.])
+	AC_MSG_ERROR([Aborting because OpenSHMEM requested, but can not build.])
+    else
+	AC_MSG_WARN([No spml found.  Will not build OpenSHMEM layer.])
+	project_oshmem_amc="false (no spml)"
+	# now for the hard part, remove project from list that will
+	# run.  This is a hack, but it works as long as the project
+	# remains named "oshmem".
+	MCA_PROJECT_SUBDIRS=`echo "$MCA_PROJECT_SUBDIRS" | sed -e 's/oshmem//'`
+    fi
+fi
+
 # checkpoint results
 AC_CACHE_SAVE
 

oshmem/mca/spml/configure.m4

@@ -16,4 +16,10 @@ AC_DEFUN([MCA_oshmem_spml_CONFIG],[
 
     # this is a direct callable component, so set that up.
     MCA_SETUP_DIRECT_CALL($1, $2)
+
+    if test -z "$MCA_$1_$2_DSO_COMPONENTS" && test -z "$MCA_$1_$2_STATIC_COMPONENTS"; then
+	OSHMEM_FOUND_WORKING_SPML=0
+    else
+	OSHMEM_FOUND_WORKING_SPML=1
+    fi
 ])