More problems with language in printing symbols

[Eli Zaretskii <eliz@gnu.org>]

There's a similar, but different problem with printing symbols in
"maint print symbols".  When the program is compiled with COFF debug
info, "maint print symbols" throws an error for some symbols:

    Error printing symbol:
    internal error - unimplemented function unk_lang_print_type called.

This happens because of this change:

    2005-06-03  Joel Brobecker  <brobecker@adacore.com>

	    * symmisc.c (dump_symtab_1): Renamed from dump_symtab.
	    (dump_symtab): New function.

The new dump_symtab does this:

    /* Set the current language to the language of the symtab we're dumping
       because certain routines used during dump_symtab() use the current
       language to print an image of the symbol.  We'll restore it later.  */
    saved_lang = set_language (symtab->language);

    dump_symtab_1 (objfile, symtab, outfile);

    set_language (saved_lang);

However, it does not check what is the value of symtab->language.  It
so happens that coffread.c creates a symtab for a "_globals_"
pseudo-file, whose symtab gets its language set to language_unknown,
because deduce_language_from_filename does not recognize such a file
name.  And, of course, trying to print symbols with language_unknown
as the current language does not give good results...

I'm unsure how best to fix that.  We could try recognizing "_globals_"
in deduce_language_from_filename, but what language to use for it?  Or
we could add some defensive fallback in dump_symtab which would not
switch the language if it is language_unknown.

Comments? ideas?