topo/treematch: silence a hwloc related warning

treematch/km_partitioning.c #include "config.h",
but there is no such file when the embedded treematch is used.

In order to prevent the embedded treematch from incorrectly using
the config.h from the embedded hwloc, generate a dummy config.h.

Signed-off-by: Gilles Gouaillardet <gilles@rist.or.jp>

ompi/mca/topo/treematch/Makefile.am

@@ -5,6 +5,8 @@
 # Copyright (c) 2011-2015 INRIA.  All rights reserved.
 # Copyright (c) 2011-2015 Université Bordeaux 1
 # Copyright (c) 2017      IBM Corporation.  All rights reserved.
+# Copyright (c) 2019      Research Organization for Information Science
+#                         and Technology (RIST).  All rights reserved.
 # $COPYRIGHT$
 #
 # Additional copyrights may follow
@@ -67,3 +69,5 @@ noinst_LTLIBRARIES = $(lib)
 libmca_topo_treematch_la_SOURCES = $(lib_sources)
 libmca_topo_treematch_la_LDFLAGS = -module -avoid-version
 
+distclean-local:
+	rm -f config.h

ompi/mca/topo/treematch/configure.m4

@@ -6,7 +6,9 @@
 # Copyright (c) 2011-2015 INRIA.  All rights reserved.
 # Copyright (c) 2011-2015 Universite Bordeaux 1
 # Copyright (c) 2015      Cisco Systems, Inc.  All rights reserved.
-# Copyright (c) 2015       Intel, Inc. All rights reserved.
+# Copyright (c) 2015      Intel, Inc. All rights reserved.
+# Copyright (c) 2019      Research Organization for Information Science
+#                         and Technology (RIST).  All rights reserved.
 # $COPYRIGHT$
 #
 # Additional copyrights may follow
@@ -77,7 +79,21 @@ AC_DEFUN([MCA_ompi_topo_treematch_CONFIG], [
                         [ompi_topo_treematch_happy=1])])])
 
     AS_IF([test $ompi_topo_treematch_happy -eq 1],
-          [$1],
+          [AS_IF([test "x$treematch_files_local" = "xyes"],
+                 [AS_IF([! test -d $OMPI_TOP_BUILDDIR/ompi/mca/topo/treematch],
+                        [mkdir -p $OMPI_TOP_BUILDDIR/ompi/mca/topo/treematch])
+                  cat > $OMPI_TOP_BUILDDIR/ompi/mca/topo/treematch/config.h << EOF
+/*
+ * This file is automatically generated by configure.  Edits will be lost
+ *
+ * This is an dummy config.h in order to prevent the embedded treematch from using
+ * the config.h from the embedded hwloc
+ *
+ * see https://github.com/open-mpi/ompi/pull/6185#issuecomment-458807930
+ */
+EOF
+                 ])
+           $1],
           [AS_IF([test ! -z "$with_treematch" && test "$with_treematch" != "no"],
                  [AC_MSG_ERROR([TreeMatch support requested but not found.  Aborting])])
            $2])