diff --git a/config/ompi_ext.m4 b/config/ompi_ext.m4
index 72f47d390d..1ba7ac1679 100644
--- a/config/ompi_ext.m4
+++ b/config/ompi_ext.m4
@@ -405,11 +405,15 @@ AC_DEFUN([EXT_CONFIGURE_M4_CONFIG_COMPONENT],[
 #--------------------
 #
 # C:
-# - c/mpiext_<component>_c.h: is included in mpi_ext.h
+# - c/mpiext_<component>_c.h: is installed to
+#   <includedir>/openmpi/mpiext/mpiext_<component>_c.h and is included in
+#   mpi_ext.h
 # - c/libmpiext_<component>.la: convneience library slurped into libmpi.la
 #
 # mpi.f.h:
-# - mpif-h/mpiext_<component>_mpifh.h: is included mpi mpif_ext.h
+# - mpif-h/mpiext_<component>_mpifh.h: is installed to
+#   <includedir>openmpi/mpiext/mpiext_<component>_mpifh.h and is included mpi
+#   mpif_ext.h
 # - mpif-h/libmpiext_<component>_mpifh.la: convenience library slurped
 #   into libmpi_mpifh.la
 #
@@ -461,7 +465,7 @@ AC_DEFUN([EXT_PROCESS_COMPONENT],[
     ###############
     # C Bindings
     ###############
-    test_header="${srcdir}/ompi/mpiext/$component/c/mpiext_${component}_c.h"
+    test_header="${srcdir}/ompi/mpiext/${component}/c/mpiext_${component}_c.h"
 
     AC_MSG_CHECKING([if MPI Extension $component has C bindings])
 
@@ -479,14 +483,14 @@ AC_DEFUN([EXT_PROCESS_COMPONENT],[
     $3="$$3 $component"
 
     # JMS Where is this needed?
-    EXT_C_HEADERS="$EXT_C_HEADERS mpiext/$component/c/mpiext_${component}_c.h"
+    EXT_C_HEADERS="$EXT_C_HEADERS mpiext/c/mpiext_${component}_c.h"
 
     component_header="mpiext_${component}_c.h"
 
     cat >> $mpi_ext_h <<EOF
 /* Enabled Extension: $component */
 #define $component_define 1
-#include "openmpi/ompi/mpiext/$component/c/$component_header"
+#include "openmpi/mpiext/$component_header"
 
 EOF
 
@@ -506,8 +510,7 @@ EOF
         AC_MSG_RESULT([yes])
         enabled_mpifh=1
 
-    # JMS Where is this needed?
-        EXT_MPIFH_HEADERS="$EXT_MPIFH_HEADERS mpiext/$component/mpif-h/mpiext_${component}_mpifh.h"
+        EXT_MPIFH_HEADERS="$EXT_MPIFH_HEADERS mpiext/mpiext_${component}_mpifh.h"
         $4="$$4 $component"
 
         component_header="mpiext_${component}_mpifh.h"
@@ -519,7 +522,7 @@ EOF
       integer $component_define
       parameter ($component_define=1)
 
-      include 'openmpi/ompi/mpiext/$component/mpif-h/$component_header'
+      include 'openmpi/mpiext/$component_header'
 
 EOF
     else
@@ -550,7 +553,6 @@ EOF
     if test -e "$test_header" ; then
         AC_MSG_RESULT([yes])
 
-    # JMS Where is this needed?
         EXT_USEMPI_HEADERS="$EXT_USEMPI_HEADERS mpiext/$component/use-mpi/mpiext_${component}_usempi.h"
         $5="$$5 $component"
         component_header="mpiext_${component}_usempi.h"
@@ -602,7 +604,6 @@ EOF
     if test -e "$test_header" ; then
         AC_MSG_RESULT([yes])
 
-    # JMS Where is this needed?
         EXT_USEMPIF08_HEADERS="$EXT_USEMPIF08_HEADERS mpiext/$component/use-mpi-f08/mpiext_${component}_usempif08.h"
         $6="$$6 $component"
 
diff --git a/ompi/mpiext/affinity/c/Makefile.am b/ompi/mpiext/affinity/c/Makefile.am
index 46573f7a46..e42dfebdaf 100644
--- a/ompi/mpiext/affinity/c/Makefile.am
+++ b/ompi/mpiext/affinity/c/Makefile.am
@@ -3,6 +3,8 @@
 #                         University Research and Technology
 #                         Corporation.  All rights reserved.
 # Copyright (c) 2010-2014 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2018      Research Organization for Information Science
+#                         and Technology (RIST).  All rights reserved.
 # $COPYRIGHT$
 #
 # Additional copyrights may follow
@@ -30,7 +32,7 @@ noinst_LTLIBRARIES = libmpiext_affinity_c.la
 
 # This is where the top-level header file (that is included in
 # <mpi-ext.h>) must be installed.
-ompidir = $(ompiincludedir)/ompi/mpiext/affinity/c
+ompidir = $(ompiincludedir)/mpiext/
 
 # This is the header file that is installed.
 ompi_HEADERS = mpiext_affinity_c.h
diff --git a/ompi/mpiext/cr/c/Makefile.am b/ompi/mpiext/cr/c/Makefile.am
index fe54fe557b..9a35c55381 100644
--- a/ompi/mpiext/cr/c/Makefile.am
+++ b/ompi/mpiext/cr/c/Makefile.am
@@ -3,6 +3,8 @@
 #                         University Research and Technology
 #                         Corporation.  All rights reserved.
 # Copyright (c) 2012 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2018      Research Organization for Information Science
+#                         and Technology (RIST).  All rights reserved.
 # $COPYRIGHT$
 #
 # Additional copyrights may follow
@@ -22,7 +24,7 @@ noinst_LTLIBRARIES = libmpiext_cr_c.la
 
 # This is where the top-level header file (that is included in
 # <mpi-ext.h>) must be installed.
-ompidir = $(ompiincludedir)/ompi/mpiext/cr/c
+ompidir = $(ompiincludedir)/mpiext
 
 # This is the header file that is installed.
 ompi_HEADERS = mpiext_cr_c.h
diff --git a/ompi/mpiext/cuda/c/Makefile.am b/ompi/mpiext/cuda/c/Makefile.am
index 719fa10989..f303cc7082 100644
--- a/ompi/mpiext/cuda/c/Makefile.am
+++ b/ompi/mpiext/cuda/c/Makefile.am
@@ -27,7 +27,7 @@ noinst_LTLIBRARIES = libmpiext_cuda_c.la
 
 # This is where the top-level header file (that is included in
 # <mpi-ext.h>) must be installed.
-ompidir = $(ompiincludedir)/ompi/mpiext/cuda/c
+ompidir = $(ompiincludedir)/mpiext
 
 # This is the header file that is installed.
 nodist_ompi_HEADERS = mpiext_cuda_c.h
diff --git a/ompi/mpiext/example/c/Makefile.am b/ompi/mpiext/example/c/Makefile.am
index 7f9e74df6c..ac8996b986 100644
--- a/ompi/mpiext/example/c/Makefile.am
+++ b/ompi/mpiext/example/c/Makefile.am
@@ -4,6 +4,8 @@
 #                         Corporation.  All rights reserved.
 # Copyright (c) 2011      Oak Ridge National Labs.  All rights reserved.
 # Copyright (c) 2011-2012 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2018      Research Organization for Information Science
+#                         and Technology (RIST).  All rights reserved.
 # $COPYRIGHT$
 #
 # Additional copyrights may follow
@@ -23,7 +25,7 @@ noinst_LTLIBRARIES = libmpiext_example_c.la
 
 # This is where the top-level header file (that is included in
 # <mpi-ext.h>) must be installed.
-ompidir = $(ompiincludedir)/ompi/mpiext/example/c
+ompidir = $(ompiincludedir)/mpiext
 
 # This is the header file that is installed.
 ompi_HEADERS = mpiext_example_c.h
diff --git a/ompi/mpiext/example/mpif-h/Makefile.am b/ompi/mpiext/example/mpif-h/Makefile.am
index fdd1c2a257..e73e4d7710 100644
--- a/ompi/mpiext/example/mpif-h/Makefile.am
+++ b/ompi/mpiext/example/mpif-h/Makefile.am
@@ -4,6 +4,8 @@
 #                         Corporation.  All rights reserved.
 # Copyright (c) 2011      Oak Ridge National Labs.  All rights reserved.
 # Copyright (c) 2011-2012 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2018      Research Organization for Information Science
+#                         and Technology (RIST).  All rights reserved.
 # $COPYRIGHT$
 #
 # Additional copyrights may follow
@@ -26,7 +28,7 @@ noinst_LTLIBRARIES =
 
 # Directory where the header file to be included in mpif-ext.h must be
 # installed.
-ompidir = $(ompiincludedir)/ompi/mpiext/example/mpif-h
+ompidir = $(ompiincludedir)/mpiext
 
 # Just like noinst_LTLIBRARIES, set this macro to empty and
 # conditionally add to it later.
diff --git a/ompi/mpiext/pcollreq/c/Makefile.am b/ompi/mpiext/pcollreq/c/Makefile.am
index 7b5f2eba83..d4aeb8ef36 100644
--- a/ompi/mpiext/pcollreq/c/Makefile.am
+++ b/ompi/mpiext/pcollreq/c/Makefile.am
@@ -23,7 +23,7 @@ noinst_LTLIBRARIES = libmpiext_pcollreq_c.la
 
 # This is where the top-level header file (that is included in
 # <mpi-ext.h>) must be installed.
-ompidir = $(ompiincludedir)/ompi/mpiext/pcollreq/c
+ompidir = $(ompiincludedir)/mpiext
 
 # This is the header file that is installed.
 ompi_HEADERS = mpiext_pcollreq_c.h
diff --git a/ompi/mpiext/pcollreq/c/profile/Makefile.am b/ompi/mpiext/pcollreq/c/profile/Makefile.am
index 9fee858081..9559574322 100644
--- a/ompi/mpiext/pcollreq/c/profile/Makefile.am
+++ b/ompi/mpiext/pcollreq/c/profile/Makefile.am
@@ -22,7 +22,7 @@ noinst_LTLIBRARIES = libpmpiext_pcollreq_c.la
 
 # This is where the top-level header file (that is included in
 # <mpi-ext.h>) must be installed.
-ompidir = $(ompiincludedir)/ompi/mpiext/pcollreq/c
+ompidir = $(ompiincludedir)/mpiext
 
 # This is the header file that is installed.
 ompi_HEADERS = pmpiext_pcollreq_c.h
diff --git a/ompi/mpiext/pcollreq/mpif-h/Makefile.am b/ompi/mpiext/pcollreq/mpif-h/Makefile.am
index e08b846df1..7282ac086d 100644
--- a/ompi/mpiext/pcollreq/mpif-h/Makefile.am
+++ b/ompi/mpiext/pcollreq/mpif-h/Makefile.am
@@ -31,7 +31,7 @@ noinst_LTLIBRARIES =
 
 # Directory where the header file to be included in mpif-ext.h must be
 # installed.
-ompidir = $(ompiincludedir)/ompi/mpiext/pcollreq/mpif-h
+ompidir = $(ompiincludedir)/mpiext
 
 # Just like noinst_LTLIBRARIES, set this macro to empty and
 # conditionally add to it later.