[m-rev.] for post-commit review: fix io section of transition guide

[Julien Fischer]

On Wed, 11 Feb 2015, Julien Fischer wrote:

>
> ranlib -c   libmer_std.a
> Undefined symbols for architecture x86_64:
>  "_MR_hash_string5", referenced from:
>      <predicate 'library.mercury_std_library_module'/1 mode 0> in
> library.pic_o
>      <predicate
> 'ops:ClassMethod_for_ops:op_table::ops:mercury_op_table:arity0:::ops.lookup_op_2_2_p'/0
> mode 10001> in ops.pic_o
>      <predicate
> 'ops:ClassMethod_for_ops:op_table::ops:mercury_op_table:arity0:::ops.lookup_op_infos_4_4_p'/0
> mode 10001> in ops.pic_o
>      <predicate
> 'ops:ClassMethod_for_ops:op_table::ops:mercury_op_table:arity0:::ops.lookup_op_infos_4'/4
> mode 0> in ops.pic_o
>      <predicate
> 'ops:ClassMethod_for_ops:op_table::ops:mercury_op_table:arity0:::ops.lookup_op_2'/2
> mode 0> in ops.pic_o
>      <predicate 'ops.lookup_mercury_postfix_op'/4 mode 0> in ops.pic_o
>      <predicate 'ops.lookup_mercury_binary_prefix_op'/5 mode 0> in
> ops.pic_o
>      ...
> ld: symbol(s) not found for architecture x86_64
> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)
>
> Since there are separate versions of MR_hash_string5 and friends for GCC
> and non-GCC, I suspect the issue is that the non-GCC version has not
> been tested.

In particular, don't you need definitions of MR_hash_string[45] in
runtime/mercury_string.c? (As per MR_hash_string[123]?)

Cheers,
Julien.