back out r9489, as the rest of the changeset clearly didn't come with this

piece

This commit was SVN r9490.

The following SVN revision numbers were found above:
  r9489 --> open-mpi/ompi@a4cfbbcac3

acinclude.m4

@@ -63,7 +63,6 @@ m4_include(config/ompi_check_icc.m4)
 m4_include(config/ompi_check_gm.m4)
 m4_include(config/ompi_check_mx.m4)
 m4_include(config/ompi_check_bproc.m4)
-m4_include(config/ompi_check_xcpu.m4)
 m4_include(config/ompi_check_mvapi.m4)
 m4_include(config/ompi_check_openib.m4)
 m4_include(config/ompi_check_udapl.m4)