* diagnostic.c (output_format): Add support for %m.
(output_printf, output_verbatim, diagnostic_set_info,
verbatim): Set err_no field of the text_info structure being
initialized.
(fatal_io_error): Delete function.
* diagnostic.h (text_info): Add err_no field.
* toplev.h (fatal_io_error): Delete prototype.
* c-opts.c, c-pch.c, dwarfout.c, ggc-common.c, ggc-page.c, graph.c
* toplev.c, config/mips/mips.c, config/rs6000/host-darwin.c
* f/com.c, java/jcf-parse.c, java/jcf-write.c, java/lex.c
* objc/objc-act.c: Replace all calls to fatal_io_error with
calls to fatal_error; add ": %m" to the end of all the affected
error messages.