[m-rev.] for review: add csharp compiler output option

[Julien Fischer]

Hi,

On Sat, 4 Apr 2015, Sebastian Godelet wrote:

> Add --output-csharp-compiler option
>
> In order to support more complicated linking scenarios linking .NET code with 
> Mercury in the C# grade, add the --output-csharp-compiler option in the same 
> way --output-c-compiler-type and --output-cc work.
> This way makefiles can use something like:
> CS_COMPILER := $(shell $(MMC) --output-csharp-compiler)
>
> compiler/mercury_compile.m:
>    Output the global csharp_compiler if the boolean option
>    output_csharp_compiler is set.
>
> compiler/options.m:
>    Define the output_csharp_compiler option and provide the help text.

You also need to document the new option in the user's guide; other than
that this looks fine.

Cheers,
Julien.