[PATCH v2] IBM zSystems: Fix TARGET_D_CPU_VERSIONS

[Iain Buclaw]

Excerpts from Stefan Schulze Frielinghaus's message of Januar 24, 2023 9:47 am:
> In the context of D the interpretation of S390, S390X, and SystemZ is a
> bit fuzzy.  The wording S390X was wrongly deprecated in favour of
> SystemZ by commit
> https://github.com/dlang/dlang.org/commit/3b50a4c3faf01c32234d0ef8be5f82915a61c23f
> Thus, SystemZ is used for 64-bit targets, now, and S390 for 31-bit
> targets.  However, in TARGET_D_CPU_VERSIONS depending on TARGET_ZARCH we
> set the CPU version to SystemZ.  This is also the case if compiled for
> 31-bit targets leading to the following error:
> 
> libphobos/libdruntime/core/sys/posix/sys/stat.d:967:13: error: static assert:  '96u == 144u' is false
>   967 |             static assert(stat_t.sizeof == 144);
>       |             ^
> 
> Thus in order to keep this patch simple I went for keeping SystemZ for
> 64-bit targets and S390, as usual, for 31-bit targets and dropped the
> distinction between ESA and z/Architecture.
> 
> Bootstrapped and regtested on IBM zSystems.  Ok for mainline?
> 

OK.