Fix builds with the external hwloc component when we use the

hwloc/openfabrics-verbs.h helper header file.

This commit was SVN r26603.

opal/mca/hwloc/external/configure.m4

@@ -111,11 +111,29 @@ AC_DEFUN([MCA_opal_hwloc_external_CONFIG],[
 
            # Must set this variable so that the framework m4 knows
            # what file to include in opal/mca/hwloc/hwloc.h
-           opal_hwloc_external_include="$opal_hwloc_dir/include/hwloc.h"
+           opal_hwloc_external_include="opal/mca/hwloc/external/external.h"
            opal_hwloc_external_ADD_CPPFLAGS=$opal_hwloc_external_CPPFLAGS
            opal_hwloc_external_ADD_LDFLAGS=$opal_hwloc_external_LDFLAGS
            opal_hwloc_external_ADD_LIBS=$opal_hwloc_external_LIBS
 
+           # We have to do some extra indirection to get the
+           # OPAL_HWLOC_WANT_VERBS_HELPER to work.  First, the
+           # opal_hwloc_external_include file (set above), points to a
+           # file here in this component. That file will include the
+           # actual external hwloc.h file (via the
+           # MCA_hwloc_external_header define).  And if
+           # OPAL_HWLOC_WANT_VERBS_HELPER is set, that file will
+           # include the external hwloc/openfabrics-verbs.h file (via
+           # the MCA_hwloc_external_openfabrics_helper define).
+           AC_DEFINE_UNQUOTED(MCA_hwloc_external_header,
+                  ["$opal_hwloc_dir/include/hwloc.h"],
+                  [Location of external hwloc header])
+           AC_DEFINE_UNQUOTED(MCA_hwloc_external_openfabrics_header,
+                  ["$opal_hwloc_dir/include/hwloc/openfabrics-verbs.h"],
+                  [Location of external hwloc header])
+
+           AC_CHECK_HEADERS([infiniband/verbs.h])
+
            # These flags need to get passed to the wrapper compilers
            # (this is unnecessary for the internal/embedded hwloc)
            opal_hwloc_external_ADD_WRAPPER_EXTRA_LDFLAGS="$WRAPPER_EXTRA_LDFLAGS $opal_hwloc_external_LDFLAGS"

opal/mca/hwloc/external/external.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2011-2012 Cisco Systems, Inc.  All rights reserved.
+ *
+ * $COPYRIGHT$
+ * 
+ * Additional copyrights may follow
+ * 
+ * $HEADER$
+ *
+ * When this component is used, this file is included in the rest of
+ * the OPAL/ORTE/OMPI code base via opal/mca/event/event.h.  As such,
+ * this header represents the public interface to this static component.
+ */
+
+#ifndef MCA_OPAL_HWLOC_EXTERNAL_H
+#define MCA_OPAL_HWLOC_EXTERNAL_H
+
+BEGIN_C_DECLS
+
+#include MCA_hwloc_external_header
+
+/* If the including file requested it, also include the hwloc verbs
+   helper file.  We can't just always include this file (even if we
+   know we have <infiniband/verbs.h>) because there are some inline
+   functions in that file that invoke ibv_* functions.  Some linkers
+   (e.g., Solaris Studio Compilers) will instantiate those static
+   inline functions even if we don't use them, and therefore we need
+   to be able to resolve the ibv_* symbols at link time.  
+
+   Since -libverbs is only specified in places where we use other
+   ibv_* functions (e.g., the OpenFabrics-based BTLs), that means that
+   linking random executables can/will fail (e.g., orterun).
+ */
+#if defined(OPAL_HWLOC_WANT_VERBS_HELPER) && OPAL_HWLOC_WANT_VERBS_HELPER
+#    if defined(HAVE_INFINIBAND_VERBS_H)
+#        include MCA_hwloc_external_openfabrics_header
+#    else
+#        error Tried to include hwloc verbs helper file, but hwloc was compiled with no OpenFabrics support
+#    endif
+#endif
+
+END_C_DECLS
+
+#endif /* MCA_OPAL_HWLOC_EXTERNAL_H */