Revert "configury: Remove --enable-mpi1-compatibility"

This reverts commit 6f904aff2c.

Signed-off-by: Geoffrey Paulsen <gpaulsen@us.ibm.com>

README

@@ -586,6 +586,11 @@ MPI Functionality and Features
       examples of how to update legacy MPI applications using these
       deleted symbols to use the "new" symbols.
 
+  All that being said, if you are unable to immediately update your
+  application to stop using these legacy MPI-1 symbols, you can
+  re-enable them in mpi.h by configuring Open MPI with the
+  --enable-mpi1-compatibility flag.
+
 - Rank reordering support is available using the TreeMatch library. It
   is activated for the graph and dist_graph topologies.
 

config/ompi_configure_options.m4

@@ -196,6 +196,22 @@ fi
 AC_DEFINE_UNQUOTED([OMPI_WANT_MPI_CXX_SEEK], [$OMPI_WANT_MPI_CXX_SEEK],
     [do we want to try to work around C++ bindings SEEK_* issue?])
 
+# Remove these when we finally kill them once and for all
+AC_ARG_ENABLE([mpi1-compatibility],
+    [AC_HELP_STRING([--enable-mpi1-compatibility],
+                    [Enable support for MPI-1.x functions removed from the current MPI standard (MPI-3.x). This option will go away in a future release of Open MPI (default: disabled)])])
+
+if test "x$enable_mpi1_compatibility" = "xyes" ; then
+ompi_mpi1_support=1
+else
+ompi_mpi1_support=0
+fi
+
+
+AC_DEFINE_UNQUOTED([OMPI_ENABLE_MPI1_COMPAT], [$ompi_mpi1_support], [whether we want MPI-1.x support])
+AC_SUBST([OMPI_ENABLE_MPI1_COMPAT], [$ompi_mpi1_support])
+AM_CONDITIONAL([OMPI_ENABLE_MPI1_COMPAT],[test $ompi_mpi1_support = 1])
+
 AC_ARG_ENABLE([grequest-extensions],
     [AC_HELP_STRING([--enable-grequest-extensions],
                     [Enable support for Grequest extensions (default: disabled)])])