DMD, LDC, and GDC compilers and 32/64 bit

[Basile B. via Digitalmars-d-learn]

On Sunday, 18 June 2017 at 16:08:36 UTC, Russel Winder wrote:
> I believe DMD, LDC, and GDC all have the -m32 or -m64 option to 
> determine the word size of compiled object and executable.
>
> I also believe there are 32-bit and 64-bit builds of the three 
> compilers. Or are there?
>
> It appears at some time in the past that some of the compilers 
> when compiled as 32-bit executables, could not generate 64-bit 
> objects and executables as they did not understand the -m64 
> option, it was not compiled in.
>
> I am asking this as I cannot test to get experimental data, but 
> I need to fix a long standing removal of a test in the SCons D 
> test suite.
>
> Is there a way to determine the bitsize of the compiler 
> executable, in the test it is assumed that if the OS is 32-bit 
> then so are the D compilers.

I'm not sure to understand correctly the question but let's try: 
With version(), e.g

version(X86){/*arch is i386 or -m32 is set*/}
version(X86_64){/*arch is amd64* or -m64 is set/}

You can know.