[glibc] powerpc: Update acosf ulps

[Adhemerval Zanella Netto]

On 02/01/25 11:12, Florian Weimer wrote:
> * Adhemerval Zanella Netto:
> 
>> Because gcc complains due how math_opt_barrier is implemented:
>>
>> ../sysdeps/ieee754/flt-32/e_acosf.c: In function ‘__ieee754_acosf’:
>> ../sysdeps/aarch64/fpu/math-barriers.h:23:30: error: read-only variable ‘__x’ used as ‘asm’ output
>>    23 |   ({ __typeof (x) __x = (x); __asm ("" : "+w" (__x)); __x; })
>>       |                              ^~~~~
>> ../sysdeps/ieee754/flt-32/e_acosf.c:94:16: note: in expansion of macro ‘math_opt_barrier’
>>    94 |         return math_opt_barrier (pi2);
>>       |                ^~~~~~~~~~~~~~~~
> 
> We can fix this by using __typeof (+x).  It removes the const qualifier,
> as far as I can see.  If we choose this path, please make the change in
> a separate commit.

I prefer to defer this to next release, since it can potentially change
code generation in a lot of places.