diff --git a/config/opal_config_hwloc.m4 b/config/opal_config_hwloc.m4
index 0180f40c25..389ffb6c9a 100644
--- a/config/opal_config_hwloc.m4
+++ b/config/opal_config_hwloc.m4
@@ -162,7 +162,8 @@ AC_DEFUN([_OPAL_CONFIG_HWLOC_INTERNAL], [
          # note: because we only ship/commit a tarball (and not the source
          # directory), the source is always expanded in the builddir, so we
          # only need to add a -I to the builddir.
-         CPPFLAGS="$CPPFLAGS -I$OMPI_TOP_BUILDDIR/$internal_hwloc_location/include -I$OMPI_TOP_SRCDIR/$internal_hwloc_location/include"
+         opal_hwloc_CPPFLAGS="-I$OMPI_TOP_BUILDDIR/$internal_hwloc_location/include -I$OMPI_TOP_SRCDIR/$internal_hwloc_location/include"
+         CPPFLAGS="$CPPFLAGS $opal_hwloc_CPPFLAGS"
          # No need to update LDFLAGS, because they will install into
          # our tree and in the mean time are referenced by their .la
          # files.
diff --git a/config/opal_config_libevent.m4 b/config/opal_config_libevent.m4
index 39a745c605..43787c9b61 100644
--- a/config/opal_config_libevent.m4
+++ b/config/opal_config_libevent.m4
@@ -192,7 +192,8 @@ AC_DEFUN([_OPAL_CONFIG_LIBEVENT_INTERNAL], [
          # note: because we only ship/commit a tarball (and not the source
          # directory), the source is always expanded in the builddir, so we
          # only need to add a -I to the builddir.
-         CPPFLAGS="$CPPFLAGS -I$OMPI_TOP_BUILDDIR/$internal_libevent_location -I$OMPI_TOP_BUILDDIR/$internal_libevent_location/include"
+         opal_libevent_CPPFLAGS="-I$OMPI_TOP_BUILDDIR/$internal_libevent_location -I$OMPI_TOP_BUILDDIR/$internal_libevent_location/include"
+         CPPFLAGS="$CPPFLAGS $opal_libevent_CPPFLAGS"
          # No need to update LDFLAGS, because they will install into
          # our tree and in the mean time are referenced by their .la
          # files.