diff --git a/config/ompi_ext.m4 b/config/ompi_ext.m4
index aa798ab3f5..17029a2563 100644
--- a/config/ompi_ext.m4
+++ b/config/ompi_ext.m4
@@ -45,8 +45,11 @@ AC_DEFUN([OMPI_EXT],[
     AC_MSG_RESULT([ompi_mpiext_list])
 
     AC_MSG_CHECKING([which MPI extension should be enabled])
-    if test "$enable_mpi_ext" = "yes" || test "$enable_mpi_ext" = "all"; then
-        msg="All Extensions"
+    if test "$enable_mpi_ext" = "" || \
+       test "$enable_mpi_ext" = "yes" || \
+       test "$enable_mpi_ext" = "all"; then
+        enable_mpi_ext=all
+        msg="All Available Extensions"
         str="`echo ENABLE_EXT_ALL=1`"
         eval $str
     else
diff --git a/ompi/mpiext/affinity/c/Makefile.am b/ompi/mpiext/affinity/c/Makefile.am
index c0471d46dd..8d8275d925 100644
--- a/ompi/mpiext/affinity/c/Makefile.am
+++ b/ompi/mpiext/affinity/c/Makefile.am
@@ -48,3 +48,6 @@ nodist_man_MANS = OMPI_Affinity_str.3
 
 # Man page sources
 EXTRA_DIST = $(nodist_man_MANS:.3=.3in) example.c
+
+distclean-local:
+	rm -f $(nodist_man_MANS)
diff --git a/ompi/mpiext/affinity/c/mpiext_affinity_str.c b/ompi/mpiext/affinity/c/mpiext_affinity_str.c
index de59be38b7..653c91ebb6 100644
--- a/ompi/mpiext/affinity/c/mpiext_affinity_str.c
+++ b/ompi/mpiext/affinity/c/mpiext_affinity_str.c
@@ -2,14 +2,17 @@
  * Copyright (c) 2004-2009 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
- * Copyright (c) 2010-2012 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2010-2015 Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2010      Oracle and/or its affiliates.  All rights reserved.
  * Copyright (c) 2012      Los Alamos National Security, LLC.  All rights
- *                         reserved. 
+ *                         reserved.
+ *                         reserved.
+ * Copyright (c) 2015      Research Organization for Information Science
+ *                         and Technology (RIST). All rights reserved.
  * $COPYRIGHT$
- * 
+ *
  * Additional copyrights may follow
- * 
+ *
  * $HEADER$
  *
  * Simple routine to expose three things to the MPI process:
@@ -38,6 +41,44 @@ static const char FUNC_NAME[] = "OMPI_Affinity";
 static const char ompi_nobind_str[] = "Open MPI did not bind this process";
 static const char not_bound_str[] = "Not bound (i.e., bound to all processors)";
 
+/**************************************************************************
+ * Utility routine
+ **************************************************************************/
+
+static void no_hwloc_support(char ompi_bound[OMPI_AFFINITY_STRING_MAX],
+                             char current_binding[OMPI_AFFINITY_STRING_MAX],
+                             char exists[OMPI_AFFINITY_STRING_MAX])
+{
+    strncpy(ompi_bound, "Not supported", OMPI_AFFINITY_STRING_MAX);
+    strncpy(current_binding, "Not supported", OMPI_AFFINITY_STRING_MAX);
+    strncpy(exists, "Not supported", OMPI_AFFINITY_STRING_MAX);
+}
+
+/**************************************************************************
+ * If we have no hwloc support compiled in, do almost nothing.
+ **************************************************************************/
+
+#if !OPAL_HAVE_HWLOC
+/*
+ * If hwloc support was not compiled in, then just return "Not
+ * supported".
+ */
+int OMPI_Affinity_str(ompi_affinity_fmt_t fmt_type,
+                      char ompi_bound[OMPI_AFFINITY_STRING_MAX],
+                      char current_binding[OMPI_AFFINITY_STRING_MAX],
+                      char exists[OMPI_AFFINITY_STRING_MAX])
+{
+    no_hwloc_support(ompi_bound, current_binding, exists);
+    return MPI_SUCCESS;
+}
+#endif // !OPAL_HAVE_HWLOC
+
+/**************************************************************************
+ * If we have hwloc support compiled in, do the actual work.
+ **************************************************************************/
+
+#if OPAL_HAVE_HWLOC
+
 static int get_rsrc_ompi_bound(char str[OMPI_AFFINITY_STRING_MAX]);
 static int get_rsrc_current_binding(char str[OMPI_AFFINITY_STRING_MAX]);
 static int get_rsrc_exists(char str[OMPI_AFFINITY_STRING_MAX]);
@@ -45,10 +86,9 @@ static int get_layout_ompi_bound(char str[OMPI_AFFINITY_STRING_MAX]);
 static int get_layout_current_binding(char str[OMPI_AFFINITY_STRING_MAX]);
 static int get_layout_exists(char str[OMPI_AFFINITY_STRING_MAX]);
 
-/*---------------------------------------------------------------------------*/
 
 int OMPI_Affinity_str(ompi_affinity_fmt_t fmt_type,
-		      char ompi_bound[OMPI_AFFINITY_STRING_MAX],
+                      char ompi_bound[OMPI_AFFINITY_STRING_MAX],
                       char current_binding[OMPI_AFFINITY_STRING_MAX],
                       char exists[OMPI_AFFINITY_STRING_MAX])
 {
@@ -59,9 +99,8 @@ int OMPI_Affinity_str(ompi_affinity_fmt_t fmt_type,
 
     /* If we have no hwloc support, return nothing */
     if (NULL == opal_hwloc_topology) {
-        strncpy(ompi_bound, "Not supported", OMPI_AFFINITY_STRING_MAX);
-        strncpy(current_binding, "Not supported", OMPI_AFFINITY_STRING_MAX);
-        strncpy(exists, "Not supported", OMPI_AFFINITY_STRING_MAX);
+        no_hwloc_support(ompi_bound, current_binding, exists);
+
         return MPI_SUCCESS;
     }
 
@@ -275,7 +314,7 @@ static int get_rsrc_exists(char str[OMPI_AFFINITY_STRING_MAX])
                 }
             }
         }
-    }
+    } 
 
     return OMPI_SUCCESS;
 }
@@ -418,3 +457,4 @@ static int get_layout_exists(char str[OMPI_AFFINITY_STRING_MAX])
 
     return OMPI_SUCCESS;
 }
+#endif /* OPAL_HAVE_HWLOC */
diff --git a/ompi/mpiext/affinity/configure.m4 b/ompi/mpiext/affinity/configure.m4
index 5192544342..95a4ca7fe9 100644
--- a/ompi/mpiext/affinity/configure.m4
+++ b/ompi/mpiext/affinity/configure.m4
@@ -2,7 +2,7 @@
 #
 # Copyright (c) 2004-2009 The Trustees of Indiana University.
 #                         All rights reserved.
-# Copyright (c) 2012 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2012-2015 Cisco Systems, Inc.  All rights reserved.
 # $COPYRIGHT$
 # 
 # Additional copyrights may follow
@@ -16,6 +16,10 @@ AC_DEFUN([OMPI_MPIEXT_affinity_CONFIG], [
     AC_CONFIG_FILES([ompi/mpiext/affinity/Makefile])
     AC_CONFIG_FILES([ompi/mpiext/affinity/c/Makefile])
 
-    # This example can always build, so we just execute $1.
-    $1
+    # This example can always build, so we just execute $1 if it was
+    # requested.
+    AS_IF([test "$ENABLE_affinity" = "1" || \
+           test "$ENABLE_EXT_ALL" = "1"],
+          [$1],
+          [$2])
 ])
diff --git a/ompi/mpiext/cr/configure.m4 b/ompi/mpiext/cr/configure.m4
index dc228b255d..757118442f 100644
--- a/ompi/mpiext/cr/configure.m4
+++ b/ompi/mpiext/cr/configure.m4
@@ -2,7 +2,7 @@
 #
 # Copyright (c) 2004-2010 The Trustees of Indiana University.
 #                         All rights reserved.
-# Copyright (c) 2012 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2012-2015 Cisco Systems, Inc.  All rights reserved.
 # $COPYRIGHT$
 # 
 # Additional copyrights may follow
@@ -16,8 +16,25 @@ AC_DEFUN([OMPI_MPIEXT_cr_CONFIG],[
     AC_CONFIG_FILES([ompi/mpiext/cr/Makefile])
     AC_CONFIG_FILES([ompi/mpiext/cr/c/Makefile])
 
-    # If we don't want FT, don't compile this component
-    AS_IF([test "$opal_want_ft_cr" = "1"],
-        [$1],
-        [$2])
+    OPAL_VAR_SCOPE_PUSH([ompi_mpi_ext_cr_happy])
+
+    # If we don't want FT, don't compile this extention
+    AS_IF([test "$ENABLE_cr" = "1" || \
+           test "$ENABLE_EXT_ALL" = "1"],
+          [ompi_mpi_ext_cr_happy=1],
+          [ompi_mpi_ext_cr_happy=0])
+
+    AS_IF([test "$ompi_mpi_ext_cr_happy" = "1" && \
+           test "$opal_want_ft_cr" = "1"],
+          [$1],
+          [ # Error if the user specifically asked for this extension,
+            # but we can't build it.
+           AS_IF([test "$ENABLE_cr" = "1"],
+                 [AC_MSG_WARN([Requested "cr" MPI extension, but cannot build it])
+                  AC_MSG_WARN([because fault tolerance is not enabled.])
+                  AC_MSG_WARN([Try again with --enable-ft])
+                  AC_MSG_ERROR([Cannot continue])])
+           $2])
+
+    OPAL_VAR_SCOPE_POP
 ])
diff --git a/ompi/mpiext/example/configure.m4 b/ompi/mpiext/example/configure.m4
index 1ae1e9f67c..29c1b42885 100644
--- a/ompi/mpiext/example/configure.m4
+++ b/ompi/mpiext/example/configure.m4
@@ -2,7 +2,7 @@
 #
 # Copyright (c) 2004-2009 The Trustees of Indiana University.
 #                         All rights reserved.
-# Copyright (c) 2012 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2012-2015 Cisco Systems, Inc.  All rights reserved.
 # $COPYRIGHT$
 # 
 # Additional copyrights may follow
@@ -20,8 +20,14 @@ AC_DEFUN([OMPI_MPIEXT_example_CONFIG],[
     AC_CONFIG_FILES([ompi/mpiext/example/use-mpi/Makefile])
     AC_CONFIG_FILES([ompi/mpiext/example/use-mpi-f08/Makefile])
 
-    # This example can always build, so we just execute $1.
-    $1
+    # If your extension can build, run $1.  Otherwise, run $2.  For
+    # the purposes of this example, we don't want it to build in most
+    # cases.  So only build if someone specifies an --enable-mpi-ext
+    # value that contains the token "example".
+    AS_IF([test "$ENABLE_example" = "1" || \
+           test "$ENABLE_EXT_ALL" = "1"],
+          [$1],
+          [$2])
 ])
 
 # only need to set this if the component needs init/finalize hooks