Re: Avoiding g77

[Mike Miller]

On Tue, Nov 25, 2014 at 23:08:41 -0800, Rik wrote:
> I think the best solution may be an explicit check for g77 and issuing an
> error message if it is selected.

How about a version check instead? The g77 program only exists for gcc
< 4. Add a check for GFORTRAN_VERSION, and if it is a GNU compiler and
the version is less than 4, issue an error? That seems more robust
than checking for the name being g77.

> I was concerned about the brittleness of the sed solution, and accidentally
> found that it is not robust.  The prologue which replaces g77 with gfortran
> is run at the end of the bootstrap sequence.  However, if the time stamp on
> configure.ac is modified, then the existing Makefiles take care of
> re-running aclocal, automake, and autoconf.  They do not run any bootstrap
> epilogue so the effect is to re-instate the default AC_PROG_F77 macro from
> autoconf which has g77 listed first.  If you are a developer, adjusting the
> time stamp can happen whenever you do an 'hg update' where there has been a
> change in configure.ac.  This is important because 'make dist' packages up
> the configure script that it finds into the tarball.  If one isn't aware of
> this oddity then the wrong configure script can be exported to everyone.  I
> checked the tarballs for versions 3.8.2, 3.8.1, 3.8.0, and 3.6.4 and they,
> at least, are clean.

Agreed, that could happen. So are you proposing to delete
bootstrap_epilogue, and we say that an error check at configure-time
for g77 (or less than version 4) is enough to avoid the original
problem this was meant to solve? That sounds like a decent compromise
to me, especially now that systems with g77 are increasingly rare.

-- 
mike