[PATCH 2/4] c/c++, asm: Use nicer error for duplicate asm qualifiers

[Martin Sebor]

> +	    {
> +	      error_at (loc, "duplicate asm qualifier %qE", token->value);

We have been making an effort to quote keywords, identifiers,
option names, and other such things in diagnostics.  In
the message above and all others like it in this patch kit
that mention "asm" the keyword should be quoted the same
way as the name of the qualifier.

Thanks
Martin