The attached patch addresses both of Tom's comments.

On Fri, Apr 12, 2013 at 1:56 PM, Tom Tromey <tromey@redhat.com> wrote:
> The intro comment to build_executable_from_specs needs an update to note
> that with_pthreads is handled locally.

Done.

> Siva> +    if { [lsearch -exact $options "with_pthreads"] >= 0 } {
> Siva> +        if  { [gdb_compile_pthreads $objects "${binfile}" executable $options] != "" } {
>
> I wonder if you need to remove with_pthreads from the options here.

Done.

ChangeLog
2013-04-15  Siva Chandra Reddy  <sivachandra@google.com>

        Add option to link testcases with Pthreads library when
        using 'prepare_for_testing' in tests.

        testsuite/
        * lib/gdb.exp (build_executable_from_specs): Use
        gdb_compile_pthreads to compile if option "with_pthreads" is
        specified.