* gfortran.h (GFC_STD_LEGACY): New "standard" macro. Reindent.
* options.c (gfc_init_options): By default, allow legacy extensions
but warn about them.
(gfc_post_options): Make -pedantic warn about legacy extensions
even with -std=legacy.
(gfc_handle_option): Make -std=gnu follow the default behaviour
of warning about legacy extensions, but allowing them. Make the
new -std=legacy accept everything and warn about nothing.
* lang.opt (std=legacy): New F95 command line option.
* invoke.texi: Document both -std=f2003 and -std=legacy.
* gfortran.texi: Explain the two types of extensions and document
how they are affected by the various -std= command line options.
From-SVN: r100377
