[m-rev.] demangle_test

[Julien Fischer]

On Mon, 8 Jan 2018, Zoltan Somogyi wrote:

> On Mon, 8 Jan 2018 10:47:20 +1100, Peter Wang <novalazy at gmail.com> wrote:
>> Since commit 244863872, it is not possible to install Mercury from the
>> source distribution. make tries to use the as-yet installed compiler
>> to compile demangle_test.
>> 
>> Can someone who remembers how the makefile works fix it?
>
> Done. I just committed a workaround, which effectively undoes that commit.
>
> I see several possibilities for compiling auxiliary programs to prevent bitrot
> while avoiding this problem with the source distribution.
>
> - Include the compiled form of those aux programs in the source distribution.
>  The size increase is undesirable, but should also be minimal.
>
> - Leave the aux programs out of their directory's standard build target,
>  but include them in a nonstandard build target that is invoked by tools/
>  bootcheck. This doesn't catch any bitrot immediately, but should catch it
>  before commit.
>
> - Leave the aux programs in their directory's standard build target, but have
>  the top-level makefile invoke another build target that omits them if a file
>  that is present only in source distributions is present.
>
> Overall, I prefer the second option. Opinions?

The second option is fine by me.  Indepenently of that, I will extend
the rotd builds so that they also unpack, build and install from the
tarball we generate.

Julien.