[PATCH] gdb: fix debug expression dumping of function call expressions

[Tom Tromey]

Andrew> In this commit I have cleaned up all of the debug-expr.exp files a
Andrew> little, there was a helper function that had clearly been copied into
Andrew> each file, this is now moved into lib/gdb.exp.

Andrew> I've added a gdb.fortran/debug-expr.exp test file, and extended
Andrew> gdb.base/debug-expr.exp to cover the function call case.

This looks good to me.  Thank you for doing this.

Andrew> -  (*pos) += 2;
Andrew>    unsigned nargs = longest_to_int (exp->elts[*pos].longconst);
Andrew> +  (*pos) += 2;

A couple times I have toyed with rewriting struct expression to not be
so incredibly obscure.  However, this is a difficult project :(.  There
are a lot of places to change and I haven't come up with an approach
better than "one enormous patch".

Tom