config/fortran: Add note about why we reverted PR #3822

* This should be enough of a breadcrumb for when we get to fixing the
   `INTERFACE` check to be strong enough to kick out gfortran 4.8

Signed-off-by: Joshua Hursey <jhursey@us.ibm.com>
This commit is contained in:
Joshua Hursey 2017-07-11 11:04:23 -05:00
parent c81795cbda
commit 20ac03c063

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@ -11,6 +11,7 @@ dnl University of Stuttgart. All rights reserved.
dnl Copyright (c) 2004-2005 The Regents of the University of California.
dnl All rights reserved.
dnl Copyright (c) 2010-2014 Cisco Systems, Inc. All rights reserved.
dnl Copyright (c) 2017 IBM Corporation. All rights reserved.
dnl Additional copyrights may follow
@ -27,6 +28,17 @@ dnl
AS_VAR_PUSHDEF([fortran_storage_size_var], [ompi_cv_fortran_have_storage_size])
# Re PR: https://github.com/open-mpi/ompi/pull/3822
# We explored correcting the following syntax to compile with gfortran 4.8
# - size = storage_size(x) / 8
# + size = storage_size(x(1)) / 8
# That allowed gfortran 4.8 to pass this configure test, but fail to
# correctly handle mpi_sizeof due to the weak test for INTERFACE in
# ompi_fortran_check_interface.m4. Until we can strengthen that configure
# check we reverted the commit from PR #3822 to keep the old logic here
# so that gfortran 4.8 will disqualify itself correctly for mpi_sizeof()
# support.
AC_CACHE_CHECK([if Fortran compiler supports STORAGE_SIZE for relevant types],